I mill my own. It's equal parts that I enjoy the control of the material I can select, and I no longer have a reputable place near me that will do it.
Many years ago we had a local supplier that would go from rough, to S4S. You selected the rough boards from their inventory, and spec'd what you wanted for thickness. They even had a 50" wide belt sander for pre-sanding and panels. You could almost come out of the shop with a finish ready board. The boards were done in "runs" so that every one of them was identical in thickness,and dimension, if you spec'd it that way.
If they were still around, I'm not sure I'd take the time to dimension my own material any longer as a routine. I've become kind of lazy as I got older.
If you can get quality material milled to your spec's reliably. Go for it.
I would still keep the planer and jointer though.
"The first thing you need to know, will likely be the last thing you learn." (Unknown)