I wouldn't say it is impossible. If it has the legs of the Wii? Not a chance. If it has the legs of say the Game Boy or DS, then sure, it has a chance.
I am not saying impossible, nothing is impossible, however I just don't think it will happen. PS4 can finish at 140M, Switch have to be either with very good legs or at least 3 more years like this one, to reach it, which I doubt both of them because next gen is coming, and Nintendo hasn't had a console with good legs lately. (even DS was dying very very fast .. I mean from 30M to 20 to 8 and it died. Within 3 years DS went from peak year numbers to death .. this is not long legs .. just okayish if not bad - from the point of % lost sales, not numbers ofcourse, 20M and 8M are good year sales for old console, however the pace is very bad, from peak to death in just 3 years, PS consoles don't do this for example.