You need to do your research. There are quite a few 3rd party games that sold more on Switch than anywhere else. Late release dates from being a new console have more to do with lower software sales than anything else.
And even if it does sell more on say PS4 or X1, the sales are still there for the developers to see profit. And that is why more and more 3rd party releases are starting to come day and date with the other versions now. Look at Wolfenstein New Blood, Mortal Kombat XI, DOOM Eternal, Crash Team Racing, Valkeria Chronicles 4, and Starlink as examples just off the top of my head.
Yeah i totally agree. I remember one Dead Cells that did better on switch but at the same time its an indie title. Maybe there is also that the AAA games don't translate too well to portable devices and vice versa. I play some indie titles on PS4 but it always feel strange. I prefer does games in portable form. When I play Dead Cells it almost feels like the screen is too far and response is off. And when you play AAA games like DOOM or Wolf on Switch it feels like the screen is too crowded to see what is going on.