But Switch is an entirely different brand from 3DS and Wii U. It's neither carrying the DS or Wii name just like 3DS carried it's name from DS and Wii U from Wii as to indicate fans that this is a direct successor from a successful brand name. Everything is different from the logo design to the color scheme to the advertising.
You don't need to share branding to be a successor. The N64 was the successor to the SNES, and it was then succeeded by the GameCube which itself was followed by the Wii.
The Master System was succeeded by the Mega Drive, which was then succeeded by the Saturn and then the Dreamcast.
The 3DS didn't end production because of mobile. It ended because it was 9+ years old and no console gets manufactured forever.
It's not a follow up to anything so much as converging two markets together. 3DS was targeting children and diehards. Wii U was targeting those same diehards and the nongamers that loved Wii. Switch marketing involved young adults, which was entirely different from before.
I agree that it convetlrged the two marksts together, but Switch marketing involves young adults, children, die hards and nongamers that loved the Wii.
They havnt had to give up any of their audience with the Switch. It's what they had in the previous generation and more.