You are comparing models who improve graphics vs a model that goes against the Switch strategy. 
Not to mention that, to take real advantage of the small increase you'd have to have a 4K TV. Another, not so cheap, extra cost.

In your words, you are comparing a core experience improvement vs a non-core experience.
Can you get how both can't really be compared? 

"Low price option has much higher potential for sales"
In theory.
GC's 99$ didn't cause a sales burst, did it?
Switch already has enough elements to make it appealing at 300. Lowering the price wouldn't necessarily make sales explode.

"with lower price option Switch will be much more popular among kids, families and casuals that actualy one of most impoartant part of market"
Lower price point can be achieved without the Mini model.
PS3, XB360, PS4, at least, showed that you don't need to lower the price that much or that you need to go after the kids market to sell 80+ million consoles. And Nintendo is now in this market too.

You don't need to directly address the kids market to actually sell to it.
Kids look up to older kids and follow trends. If you sell to the older kids you'll eventually reach the younger demograhics. 

"There is reason why Nintendo released very low price option for 3DS in form of 2DS"
How many times has Nintendo offered a model that could be deemed inferior to the original versus the number of revisions that could be deemed superior to the original version?
2DS is the exception, not the rule.
And let's not forget that if 3D has been relevant and had not caused a backlash at the time, you probably wouldn't have gotten a 2DS.
Also, an investment in 2DS, in the form of 2DS XL, was - and probably is - the last revision ever for 3DS. Before that, you had Nintendo betting on evolving the regular 3DS.

What you are basically asking is for Nintendo to simply overlook the success they had with it's current market and the weight of the Switch (hybrid concept) and just do a U turn and go back to their old ways (kids, families).
It just doesn't make sense: this new Nintendo is where they should put their money and time on - now that they are being successful.
The other market can come later. There's no rush and it would even be sending the wrong message to it's current market!

I don't comparing anything, you wrote "why should people opt for a mini version when they can't get the best experience on the original Switch? The potential of a such a model would be limited by default", I simple gave you example of another best experience.

How GC can be in that comparison when we had only one version of GC!? Again you dont make any sense, I will not even read rest of your post or even try to answer.

Another example of why you shouldn't only look at price without factoring in value: Wii U Basic vs. Deluxe. The system didn't sell much yeah, but of what it did sell while the Basic was on shelves, the majority was the Deluxe model despite being $50 more expensive. The Basic model was discontinued in just a year.

Going back to the 2DS, I remember hearing that the more expensive models sold better, but I can't find a source for this. However we still have the ultimate source, sales! Looking at the effect it had on overall sales, it barely did anything. 2013 when the 2DS launched was the system's best year, but not by much. 14m compared to 12.5m in 2011 and 13.5m in 2012. Next year 2014 sales dropped to 8.5m.

You've misunderstood my post: I wasn't claiming Switch is definitely losing momentum, but rather the Wall Street Journal report states that's the reasoning behind this supposed hardware redesign. See this USGamer article for a clearer indication of what Wall Street Journal say in their original report, which is behind a paywall. 

If you read my post properly, you'll see I pointed out that a hardware refresh was only a matter time. I speculate that if Switch has lost momentum, that's likely down to this year's software line-up more than it is any hardware issue. I point out that Nintendo's major 2019 titles are yet to launch, and, importantly, that I think we should wait until Nintendo's second quarter results later this month before stating whether or not the system has lost momentum. 

Offcourse, there is point of value also, and Deluxe was much better value than Basic model, compared to Basic model Deluxe model offerd much more equipment, much more internal memory (Basic had like 2GB memory available to consumers), and game, so all that for just a $50 more was much better value. But thats quite difrent story compared to current Switch story, best comparison with current Switch and Switch Mini/Pocket would be comparison with 3DS and 2DS.

2DS penetreed 3DS into kids, familes, casual market, only after 2DS some people start buying multiply 3DS consoles for home esapcily after 2DS price cut, for instance buying 2DS for each of their kid. 2DS didn't need to sell better than 3DS XL for instance, but it was aiming at different demography on market compared to 3DS XL, so point is to offer different price point for different type of revisions that aiming at difrent parts of market. You can bet that without 2DS, sales would be much worse than they are.

I understanded you, but they are wrong, for instance "While not failing, the Switch is certainly not selling as much as in its first year when the Switch first became available in March 2017", is clearly wrong, Switch until now was selling very similar compared to last in same time period, and like you wrote this Holiday season will destroy last years.

"I don't comparing anything"
Yes, you are: "Buy your point Pro and X would need to be best selling option of PS4/XB1 because they offer best experience for PS4/XB1".And this is what i addressed (best experiences).

You are comparing two different realities to try and make a fair conclusion. But it's a flawed conclusion as you ignored what would be/is different between Pro/X and a Switch +.
Thus, opting for the best option in Switch +'s case would not be/isn't the same as opting for the best option in the case of Pro/X.

"Low price option has much higher potential for sales"
In theory.
GC's 99$ didn't cause a sales burst, did it?
  

You claimed that low price options have higher potential for sales.
I responded that that is not necessarily the case. And it's not because it's a revised version (specially one that results in an inferior product/experience) that really changes that.

Right - but we don't have quarter two shipment figures yet. When they come through, they might be down on the same period last year, or they might not be at the level Nintendo desire. It's still possible that's the case, but we'll only know for sure at the end of this month.

Then why have the mini version if the point was to cut costs(for the custumer), if in the end they will have to buy acessories to actually be able to play every single game the system offers?And no, you dont need a pro controller to have the full experience.I mean, as far as I know, no game requires the pro controller to be played.Nor the NES Joycons.

They won't have to buy the accessories, it is just an OPTION. Most Switch games work perfectly fine with the Pro controller or a third party controller, many of them even better than with joycons.

How many and which Switch games only run with Joycons? Not every Switch owner wants to play 1-2-Switch.

Also Nintendo wants to bring more than one Switch system into a gamer's household. Different form factors can help with that plan. I wouldn't buy a second normal Switch with all the same advantages and disadvantages (and a second dock I don't need) for another €300... but I might buy a €200 Switch mini/lite with better battery life, lighter weight and smaller dimensions for mobile use additional to my standard Switch, which would stay in the dock.