I think pretty much anyone out there with a CNC machine and an interest in making lowers is already doing so.

The cost to make just a few of them by borrowing a CNC machine would probably far exceed the cost you would pay for currently available ones. that is just a guess, maybe someone would be nice to let you use one and do it cheap...but there is set-up, the computer input for all the dimensions, the tooling, the time, the power used, the wear on the machine, and any extra materials all add up.