Today port a ps4/xone game is a pain job, imagine when ps5 and next box arrives? The gap in specs will be brutal.
Or nintendo make a Switch pro/Switch X or the developer makes their game only for the console. A safe way for those who make games today only for 3ds, indies and companies with short budgets.
I do not see any difficulty in people having a switch and a ps4 / 5 or xone / next box together.