If Switch 2 comes out let's say Spring of next year, Switch will probably have about 150m sold to consumers around when next gen starts. But unless they do price cuts, Switch sales will fall to barely anything once the next system is out. Even if S2 costs $400 (which seems likely at this point with no OLED price cut cuz they aren't gonna price next gen concurrently at same price as the predecessor), that's gonna pretty much kill off all Switch sales except the $200 Lite. So without price cuts, or unless they somehow hold off next gen launch until late next year which would be a very bad business decision for their year, Switch ain't hitting 155m. 150m for sure and then it may limp to like 152-153 million, 155m not without price cuts, and no reasonable path to 160m.
Remember sales of Switch have been quite poor for the past 12-18 months everywhere in the world other than Japan except for during the Mario movie / TotK boost which lasted a couple months last year. Switch sales have been limping outside Japan for a while now. The only thing that will juice Switch sales at this point is big price cuts, which are probably not gonna happen. And as soon as next gen starts nobody is going to be buying an old system priced only slightly lower than a brand new next gen system.