Wii was selling beyond anything released at that point and especially Sonys home console gaming (PS3) was struggling so it made more sense to try to copy the things Wii did. Switch at at the moment is selling like early PS4. Why would Sony change from their successful approach to something different that at best would give them same results as the current approach? Makes no sense.
With three consoles all doing the same thing? No. The gaming world needs variety to thrive. The switch has been successful because its a differentiated offer to the other two boxes that are basically the same outside of exclusives.
THIS, for god's sake. Enjoy your Switch, but please please PLEASE stop asking the same question over and over and over again. It won't happen, lots of people couldn't care less about portability and still care very much about good graphics. To each his own