Not all professionals seek to have a huge display all of the time.12-inch is way too small for professional usage when you need to spend long hours in front of it.
Some connect their small laptops to big screens.
Or some just have a bigger screen laptop for some work and enjoy a small one for the go (as my case).
I work many things on the cloud, so it is easy to swap between one and the other.
I even bought my MacBook Retina 12" and absolutely love it. I even bought it new, in eBay, when it was already was discontinued and was at a high price.
Yes, I also have the new MacBook 14, but although I did got to the old calibration panel in this one, still the colors of the the MB 12 for everyday use are much more rich and saturated than the new Liquid Retina XDR display of this MacBooks (although they can be brighter), no matter what setting I fiddle with.
So I have much to love of the MB12 and look forward for buying a the New MacBook Pro 12 with an M2Max!