More per household is probably due to it not needing a TV to be played with. Not because it's seen as a portable.
I can see a 149-180$ as a good price for handheld users, but seeing as it is 300-329 and it's selling this well, i only see that happening in a few years.
I don't know what revisions you are imagining, but anything that makes it onesided (either portable or home console) will only make it seem like the inferior version.

Indies and kid/family games are common in both portable and home consoles alike.
Japanese games are pretty much of console games. Actually, i think the only two handheld i've seen coming to Switch are that SE game that was announced recently and the other is a port of a GBA game. Don't recall the game.

The real 3DS support didn't end a lot after Wii U's, anyway. And with the unifying od the development teams we should have seen more handheld games and we didn't and aren't.
Nintendo will most certainly release some handheld IPs, but seeing as it is pushing Switch as mainly a home console, i'm pretty sure the majority of it's titles will be home console oriented. Specially if 3rd party home console titles keep coming and really start being sucessful.

That 2nd party/affiliates argument is something that can't really be proven or disproven right now. We'll have to wait and see.
And just by looking at some of those names, i'm already remembered of franchises that are also on home consoles or started as such: Mario Party, Fire Emblem, Yoshi, Paper Mario, Luigi's Mansion.

I can see the holidays shaking the userbase's age up, but i don't see it as a sign of an actual change.
That sample shows that during the non-holiday period it's not kids who are buying it. And not just buying, but actually owning it. 
Honestly, with that in mind, and seeing Switch's release schedule, i don't foresee a change in user demographics anytime soon. 

Yeah, Labo is probably the thing that can't add a lot of kids to it's userbase.

I naver said it wouldn't be possible for Switch to be a success without 3rd parties. I said it could suffer IF the gap increases, which could lead to lack of support when PS5 and XB2 arrive. It's not the same thing.
What i'm saying is that, for the time being, everything is working in Nintendo's favour (portability, 1st party games and userbase). Therefore, the best course of action should be leveraging those strengths to expand it's userbase.

So the best thing Nintendo could do is take advantage of that while it can.

Not needing a TV=portable/handheld. The most popular sku of 3DS was $199 so thats a good price point for making it a 1 per person device and for primarily handheld gamers to get one.

Making a handheld only or console only version will be seen inferior to people who like both, but not to people who only like one or the other.

They are pushing it as a console currently because of the price and to keep it coexisting with 3DS. In the next year or two when the price drops, 3DS is phased out and games like Pokemon/Animal Crossing come out then it will be very much pushed as a handheld as well.

The 3rd party support of Switch will not be affected by PS5/XB4. Like i said, the majority of its 3rd party upport comes from indie games m, Japanese games, kid/family games & previous generation ports/remasters.

These type of games do not typically require big budgets or high end specs so Switch has little risk of losing them.

Like i said to Curl, Switch 3rd party supprt can be compared to the consolidated support of Wii U, 3DS & Vita. Those 3 systems were underpowered and recieved very few AAA multiplats and so far Switch hasnt recieved many either. You cant lose something you never had so lack of multiplats will not be a factor.