There will be an impact, but not a big drop-off. When Switch's sales really start to drop off, it will just be because the Switch has been out for a while. In general, I don't think there will be too many consumers who say "I really want a Switch, but I better get a PS5 or Xbox Series X instead". Or even "Now that PS4 and Xbox One are cheaper than ever, I'd rather get them than a Switch." They'll exist, but they'll be the minority.
Lifetime Sales Predictions
Switch: 151 million (was 73, then 96, then 113 million, then 125 million, then 144 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 57 million (was 60 million, then 67 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima
