PS consoles are about longevity as opposed to spikes in sales. I’m sure you’ll agree with that.

The PS4 Pro plays 0 game that the base PS4 cannot play, unlike the 3DS. You say mid-gen refresh is the future - Nintendo has been doing that for generations now and by releasing systems with exclusives as well. And of course Nintendo will do that with the Switch, how else would they prolong the life of the system? It’s what they’ve been doing for a long time now. The other thing is that the PS4 Pro is still way above mass market price and makes up a fraction of the PS4 sales and is not intended as a replacement for the regular PS4.

More product lines is simply going to become the norm. Apple would sell far less iPhones if they only had one damn iPhone. Same with Samsung and so on. 

The whole "we make only one system and that's it barring just minor changes for 5-6 years" is outdated 1980s/1990s thinking today. Every hardware line is going to embrace multiple product SKUs with differing specs, in large extremes at that. Switch Pro is coming. 

PS4 Pro makes Sony more money than the regular PS4, those higher price points are more lucrative and reap console makers more money, that is probably true of XBox One X too. You can keep the premium price but as time goes on the price of those components drops, so you eventually you start making real nice money from that high end model. 

Switch Pro will be different from the DSi and New 3DS IMO which were minor upgrades, I think you will see a full on 2x-3x performance increase all across the board, just like PS4 Pro and XBox One X. 

You know how I know that the 1 hardware per generation is still valid and not outdated? Because the PS4 is still cruising. It works for phones because it gets subsidised with phone plans. And they don’t have to maintain compatibility like consoles do. Have a console manufacturer try and do that with a console and see how that works out. Nintendo do it because they have no choice as they would sell way less hardware without revisions.

The 3DS revisions play games that the original 3DS cannot. That’s a major difference compared to the PS4 Pro and base PS4.

PS3 also had stronger later year, now PS4 has its 4. and 5. years like best ones, so saying "Switch finally winning a month against a 5-year old system" dont makes point because that 5. year for system will be best or second best year for system. Actually its impressive that Switch is taking even any month in one of bests PS4 years.

2018 won’t be in the PS4’s best years. I think it will be the PS4’s 4th best year in the US. The sales over the years have been more or less constant anyway.

Like I wrote, it will be first or second best year for PS4, probably second, but my point still stands.

Well, your point doesn’t stand if it isn’t the first or second best year for PS4, which I don’t think it will. It also doesn’t stand because as I explained the PS4 isn’t about a huge peak and then dropping off quickly. It sits at a high amount for several years.

It stands because this year will be best or second best year in US for PS4. Its also stands because we again talking about one of best PS4 years, so saying "Switch finally winning a month against a 5-year old system" losing point because we talk about one of best PS4 years, so Switch is battling against one of best PS4 years not worst one like you sounded. If talk about same period sales, Switch is selling on pair with PS4.