The closest to a Vita Smartphone would be a current xperia z3 or z5 combined with PS4 controller and phone holder.I own that setup and use it to play the classic final fantasies on my phone. (Soon coming FF7) Square is doing a good job in my opinion with supporting phones. It works perfectly the experience is great. Also Graphics are probably better than on Vita (never used a Vita so cant say for sure). Plenty of deeper games/classics out there which support the PS4 pad. Also N64 Emulator is a ton of fun. The offer on games for Android I want to play is way bigger than the time I have to play them.

Two failures don't make a success.

I think it would have been a struggle to brand it, ""playstation phone" wouldn't work IMO. They tested the waters with Xperia Play but its one of those things where you can't go in have hearted. Xperia Play was a weak phone, with no real gaming credentials other then a few PS1 titles and undesirable as a device full stop.

Its something that should have been done before the end of the decade really. I still thinks theres potential for it in Japan, especially with streaming becoming a thing

Well its questionable. Would combining the numbers from each respective devision make for a more successful device with streamlined production? I'd say likely.

Its something that was worth sony trying at some point, especially at the turn of the decade where more people were gaming on their phones and the handheld market was decreasing.

https://oneplus.net/one

You think the console market is flooded? How much does the average cell phone that's not made by Apple sell?