I think when ps5 and xbox 2 come out switch will be slow down considerably.
Yeah, Switch will than definitely start failing of a cliff. :D
Joke aside, when PS5 and XB2 come out, Switch will still have two its main points for selling, Nintendo games and hybrid nature that PS5/XB2 probably will not have. So nothing really will change for Switch, especially because Switch will probably in that time period have price point of around $200 with already strong built in line up of games while PS5/XB2 will be $400+ consoles. You can look even current situation, PS4/XB1 dont effect on Switch sales and Switch sales dont effect on PS4/XB1 sales, same will be with PS5/XB2.