...Sony's most prestigious teams haven't shipped any handheld games. That's telling in of itself. Maybe the platform wouldn't have been still born if there was more internal push from the top teams. Especially when the vita was a damn nice piece of kit.
Highly, highly doubtful that "top teams" would have saved the day. AAA production values or pedigree talent doesn't really sell handheld games the way it does on console/tv. People always argue that "Nintendo puts its top men on its portables", but...
A) never at AAA budget levels (I'm trying to think what the most produced portable game Nintendo ever made would be, maybe Codename STEAM with all the voices and the new engine production? a Pokemon or Mario Kart will accrue budget costs in manpower over the time designing and polishing, but we don't have a clear answer yet what they actually spend on game designers, I'm guessing those guys are not rich)...
And B) Nintendo's way is a different way to run a company, something pretty specific to Japan that we don't have here. Nintendo is one big office, and people move around; Naughty Dog or Guerrilla or Sucker Punch aren't like that. (989 was a little that way back in the day, with producers working on a few dozen projects up and down stairs and designers and programmers and audio techs working on bits of projects rather than one big master work. SCE Santa Monica has that a
little bit because they also operate an incubation group, but their primary focus is God of War or whatever's after; SCE San Diego is a little like that too, with its baseball team but also a lot of sound and mocap and other facilities.) SCE Japan Studio is old-school like Nintendo, and its talents mix up across projects, but because SCEJ is so small now and has struggled so much, you see little out of them overall and have few expectations for where team members should be. (Still, one of their few known names last made Gravity Rush, and Soul Sacrifice and Freedom Wars were not exactly B-team efforts.)
It's a different and a little bit of an old way of doing things that's not as familiar to western approaches, and most of what Sony does that people assign AAA-studio designations to is not compatible. That said, Sony isn't above it necessarily. They had Zipper make a bunch of SOCOMs for PSP and Unit 13 for Vita. They had their own teams make the home and portable versions of PSASB and ModNation; Polyphony Digital took time out of its impossible schedule to finally deliver on its PSP GT promise. MLB and Hot Shots weren't farmed out. Maybe AAA studio Naughty Dog will never make a Vita exclusive (like AAA studio Retro will probably never make a 3DS exclusive... they did make a port, of all things,) but AAA studio Media Molecule did make a Vita exclusive, and let's also not leave SCE Bend out of the "Top Team" discussion because they are extremely good.
You are overall right that Sony does not value its portables the same way Nintendo values its, but a decade in the portable business, Sony has learned (what many might have been able to tell them on day one) that Sony portables require different levels of support than Nintendo portables because Sony brands don't transfer to portables like Nintendo brands. Making console-quality God of War and Killzone and Syphon Filter and Hot Shots and Motorstorm games will not pay off in equal proportions, no matter if they're exactly like the console game or offer totally unique experiences. (With games like Killzone, Sony tried it both ways; both good Killzones, neither blockbusters.) And since Sony is a AAA-oriented company, little games made for portable like Patapon and LocoRoco may be successes but won't draw much recognition. Sony couldn't do things Nintendo's way, they had to do thing's Sony's way, and unfortunately that way only led to moderate success the first time (as far as software sales go) and has lead to a dead end in this generation.