It’s certainly possible, at least. As it stands, the Switch will likely sell through 85 million units (they’ve hit close to 82 million based on Japanese sales alone) for fiscal year 2020. The Switch’s momentum appears to be growing, and with the Pro looking likely for this year, a modest increase in units sold YoY to 32 million seems like a solid prediction. That’d put the Switch 117 million by the end of fiscal year 2021.
I think 2021 will likely be the Switch’s climax, however, so we can expect a drop off for 2022. I think 23 million would be a pretty solid estimate. That puts the Switch at 140 million. Then 2023 would be another drop off, and likely Switch’s final full year, so lets say about 12 million. 152 million. I think the Switch can easily sell another 5 million after the release of its successor...and that’d be enough to push it past the PS2.
Given how well the Switch sold in 2020, it’s foolish to discount its ability to beat the PS2. So long as Nintendo doesn’t outright discontinue it before 2024, I would personally bet on it happening.