Also, RE: CNC ready/safe files.

CNC is only a little different than 3D printing in this regard. A step file for a cube that can be 3D printed can also be used to generate gcode to cut that cube out of any piece of material.

but you have to generate your CNC gcode based on the shape of the material you are going to cut it out of, so there is no one-size-fits-all gcode file for making the same part from any block of any material. But this is analogous to not being able to take gcode from one printer and one material and run it on a different printer with a different material.

As long as you can cut a feature with a standard tool/bit/endmill, your only issue is how to hold the material in the proper orientation for your machine to cut it. Creative work holding is what allows you to make more complex parts with a simple machine.

Yeah the cost benefit analysis on a $1,000 CNC machine is pretty easy to see. My 3DP setup was less than that, and even if you take out all of the pews, I've probably broken even already on other stuff that I've printed that I would've otherwise bought on Amazon.

My guess is that a $2,000 desktop mill is what it would take for people here to start playing around with it. The Carvera one I looked at fits the bill for desktop, fully enclosed, clean, easy to use, but it's sitting around $5,000. I think you'd have to have some need or interest beyond pews to buy something like that, or enough hate of Rare Greed or love of the 2A to go all in just for that.

If I had a CNC mill, was a bit of an artist, and had enough design skills, I'd dissect every Gucci AR, figure out why their machining justifies such a high price point, and throw all of those features together. Then I'd release the file as "the $1,000 lower receiver" on the index, so that everyone could feel like they'd broken even on their first project.