2.1M

If the Switch does indeed do 2+ million this year that would still be excellent sales for a system in it's 10th year on the market.

2.5 million , thank you to Tomodachi game

around 2m maybe abit less is my guess.

Correct. But not even close to what PS2 was pulling off at that age. Still, Switch sold faster than PS2 and has a more popular successor. And PS2 was selling for $99.99 a lot in its last years. Even adjusted for inflation, still pretty cheap. 

This might be the last year Switch sells over a million units if there's another big drop and it sells around 0.75-0.95 million units in 2027. I would be very surprised if it cracks over a million in 2028. 

It's probably going to decline another 60-70% this year, so 1.5-2M.

Ranges are too narrow at this point. I’d say anywhere from 1.5 to 3.5 million is a safe probably 95% probable range. But in 3 months things will be clearer.

This is excluding potential interventional factors like price drops and new models which could easily add an additional 1-3 million to the probable number for the year, making it 2.5 to 6.5 million (that 6.5 million would be like Switch TV for 50 to 70% the price of the original).