If Switch 2 launching this year I don't see it passing PS2. Only ways is if Nintendo manufacture more and continue to sell for 2 more years along with Switch 2.
But I don't recall Nintendo kept manufacturing previous gen(especially for more than a year) as new Gen begins.
It depends on what you're looking at.
Remember Switch is a hybrid, so bear their handhelds in mind too, and usually the older system hangs around for a while after the replacement hits, often getting a slew of final bangers and a Pokémon before they turn the lights off.
I mean there's still n2DS XL's getting sold even now in Japan. Barely any mind you, but I would be shocked if we didn't see Switch 1 still on sale into 2026 quite honestly.