Need help replicating a baseboard
If you want that profile in one piece, it looks like you'll need some fairly specialized equipment, Like a moulding machine or planer/molder and possibly custom knives. In any case all would seem to make the job more complicated than simply using multiple pieces.
For the main board, just running the whole board on a router table with a roundover bit would give you the top profile. Short of planing a very thick board, 6/4 or better on a shaper or molding machine, I don't see any reasonably feasible way to get the middle profile. Buying or even making your own 1/2 round is actually pretty easy. I could probably duplicate that base pattern on the entire room in a couple of hours. You could also put the center piece on the main base before putting it on the wall. As for the quarter round at the floor, it would actually be preferable for that to be a separate piece, since most floors are not perfectly flat. As one piece you would have to either put up with rather visible gaps where the floor dips, or scribe it in, which would be WAY more tedious than making the baseboard out of multiple pieces.
As a separate piece, the Q-round is flexible, so it can be held in place where the floor dips while nailing it in place.
To make your own half round, just buzz a board across the router table with a 1/4 round bit, flip the board, run it again, then cut off the rounded edge with your table saw, or even a circular saw if you have a guide, a quality blade, and a steady hand.