Because it worked well for over 20 years, and it could still work well into the future. Handhelds and home consoles are two different types of experiences, and I happen to like that paradigm.

As for brand names, it is interesting how they've only had two marques that lasted two generations a piece: Nintendo Entertain System and Wii. Maybe they could resurrect the former and see if that works out in the marketing side of things. Maybe some retro thing that reminds people why they started "Playing With Power" in the first place all those generations ago. That could be specifically targeted at older gamers who grew up with Nintendo in the 80s & 90s. Of course, the system itself would have to be the equivalent of what the NES and SNES were in their days: plain old ordinary systems that didn't do anything particularly unique (as opposed to innovation for innovation's sake like with the Wii brand), but had a ton of great games both first-party and third-party. I've already said this several times the past couple of days, but Nintendo needs to not be afraid of making a console that competes directly and on the same level as Xbox and PlayStation. Third party titles, online infrastructure, etc., should be non-issues, meaning the Big Three should be more or less the same in those regards. Let the consumer's deciding factors be about whose exclusives appeal to them the best, whose marketing resonates with them the best, whose hardware is the most reliable, whose customer support is the best. Make a system that could cover almost all of most gamer's needs. I think such a system would do extraordinarily well without having to rely on an interesting but fundamentally unnecessary innovation that may or may not pan out.