Uhmm, yeah, no.
Many of the lower priced AR lowers have been well-known to have out of spec holes in the lower. Wrong place, wrong size, you name it & it happened. Anderson was one company that had those issues, I doubt they were alone on that.
There is also a large variation in the alloy mix on lowers. I'm not a chemist, so I can't explain what those variations are, which ones are better, etc. But I have held ARs from companies like Black Rain, Daniel Defense, etc. There is a definite difference in how the lower felt from the cheap one to the $2K one. Now, would the cheap lower work with the $2K upper? Probably. Now, do you want to stake YOUR life on that? *I* wouldn't.
My .o2