They once did, for instance the Stanley #52 discontinued in the 1940ies.
I understand why you would want to buy one, also why others think its way to easy to make to justify buying it.
[rant]I just spend the entire day so far to drill 1 hole and cut a piece of silver steel in two which is still not finished. Spend most of the time moving stuff around, locating the tools, finding a blade that was now dull on the full length. The silver steel is now cut about 1/4 of the way. Holding the piece in some nuts in the machinist vice, which sits upon a small wheeled bathroom drawer closet. Me standing in the doorway with the door knob in my side and hitting me elbow on the door on each stroke.
Drilling was also fun, trying to hold the round thing in not so accurate V blocks I made for this job with my LN shoulder plane. With the piece on the drill press table at the lowest position the 10mm drill bit is to close to the table for the piece to fit under it. With the piece on the drill press foot and the drill fully extended down its to high to even touch the piece. So the piece has to sit on top of a stack of scraps. Finding the centre without tripping the stack while looking directly into the sun is not that easy also.
Without the right tools, everything you need at hand and enough place to work things are much much much easier.[/rant]