Im just gonna make a small little prediction for the next few years on Switch Sales
2021: 22 - 24 Million
2022: 16 - 21 Million
2023: 11 - 16 Million
2024: 7 - 10 Million
2025: Likely New Console But Switch would still get a few million 3 - 7 Million
Total I think the switch could sell
Lowest: 115 Million (This is unlikely because 2021 will have some amazing games that'll probably push the sales to 95 - 100 million so an extra 15 million will be so easy to get that this number is almost impossible)
Likely Amount: 125 - 135 Million
Highest: 140 Million or more (this is almost impossible unless the switch can somehow release Outstanding Games or switch pro (kinda like the wii and the wii u) except the switch pro actually has a good reason to be purchased