If you mean the sales after the other 2 are released, then of course switch will be past it's best years and probably sell more than PS5 and NeXtBox for 2 years like the PS4 did over the switch. Than switch will naturally wind down and sell less than the power twins. But if you mean total sales, switch is charting pretty similar to PS4 so 90+mil is guaranteed. I don't think NeXtBox will sell that well and not sure about PS5. Sony has a history of messing up after a successful console.
Just a guy who doesn't want to be bored. Also