It seems pretty difficult to put a fine point on how much the Switch will sell in the end without knowledge of how they plan to delineate what comes next ( A New 3DS style "Pro", An outright Switch 2 with backwards compatibility, Or something half way inbetween more akin to the GBC ).
I voted for the 130-155 Million range simply because I see 130 as the floor even if their was no successor whatsoever. I am confident they will finish this fiscal year with between 107-110 million units and if the software slate for the next fiscal year is anywhere near as good as we are expecting I believe that 18-22 million units is very realistic for the fiscal year ending March 2023. That would put it's life to date total anywhere for 125-132 million in March '23, even on the lowest end of that estimate Switch would pass 130 million by fall of 2023.
How far it can go beyond that is still up in the air, and may very much come down to the semantics of what they decide to call their next piece of hardware after the OLED and how they bundle the reported numbers, but the potential certainly exists to become the new #1 selling console.
I think the overall promise of the the Switch and Nintendo ecosystem/future is what is most interesting. I have no doubt the PS5 and Xbox Series will do very well on the back of their blockbuster titles, and in Xbox's case more specifically the affordability of it's ecosystem, but I can't help shake the feeling that they are only really able to pull from audiences that were already theirs. Meaning that if PS4 and Xbox ONE did not draw you in, what do these new consoles do differently that would change your mind (I admit that it is still too early in their respective lifecycles to really make this judgment, this is just the impression I have for now). When I look at Switch I can see it drawing from people who were into the Wii/Wii-U and more family/party games or Nintendo home consoles in general, Nintendo DS/3DS ( I feel like this would include most of the core Nintendo fans ), PSP/Vita as it is really only the machine to still offer a somewhat similar experience, as well as some people who were more heavily into Sony's output on PS1 and PS2 and the type of games that were lost as Sony refocused itself towards the end of the PS3 lifecycle. I can even see it bringing some PC players who are more interested in indies and small scale ( Not online multiplayer focused ) titles into the console fold, though I doubt this group represents as large a portion of the Switch base as the others. This is of course a very rosy view of Switch/Nintendo potential and the Switch obviously only brings a portion of each of the aforementioned markets which do not transfer over in their entirety. The overall maybe messy point I'm making is that it seems to me that the Switch is able to pull it's audience from more formerly disparate groups, as compared to the new PS5 and Xbox which would pull mostly from their direct predecessors, and that seems very healthy to me.
I have made this post entirely to long to convey a pretty basic point, haven't I.