I disagree, as sometimes other people want to use the living room television, and it is nice to be able to quickly change to a handheld screen and let someone else watch TV for a bit.
I just don't think that's a super useful feature to many. At least not among the US middle class and above as we're mostly in decent sized houses with multiple TVs. Hell even growing up lower middle class in the 80s and 90s my parents got my brother and I small (13" I think) CRTs for our bedrooms so the living room TV wasn't getting hogged by gaming.
It's a useful feature for some for sure, and probably more so in Europe (and especially Japan) where small house/condo/apartment living is more common. But less so in North America, and less so in households with more money (which are likely to buy more games and hardware) as they're more likely to have the funds and space for multiple TVs.
Like... if the Vita had TV out, would it be classified as a hybrid?
If it had a dock that allowed it to overclock and put games on the TV at 1080p vs. it's native resolution? Sure. If it just had a TV out? No.
Sony and Microsoft are useless, but if Nintendo wants to throw away 20 years of hardware and software purchasing amounting to several thousand dollars then more power to them.
They're throwing nothing away. They're trying to find ways to increase attach rates and profits by being able to sell all their games to everyone who buys their hardware, and hopefully sell more hardware by having a lower price and some features that differentiated them from the competition (more attractive as a secondary device than grabbing a PS or Xbox if you already own the other).
Besides, all they have to do is stay relevant until internet capacity is at the point that everything is digital and in app based ecosystems and they can have their own Battle.net like ecosystem--only on multiple devices with all processing done in the cloud and thus no need for dedicated hardware beyond controllers and other peripherals. Dedicated consoles and portables will be gone in 10-15 years.