Honestly, if Switch breaks 15M this year and a successor isn't announced until next year, I believe it still has a shot. Here is what the Switch would be at if it follows a similar trajectory as Wii, which many believe declined rather quickly
End of 2022: 122M
End of 2023: >137M (15M)
End of 2024: >147M (~10M)
Lifetime: >152M (~5M)
I'm using FY data for convenience. But Switch's 2022 appears to be comparable to Wii's FY 2011