There's obviously an upper limit but we are very far from reaching that. Satellites are made up of many components much of which is aluminum most composed of bauxite. Apparently we have a lot reserves and are able to meet demand for quite awhile into the future.[1]

Worst case we can always recycle that space junk but it's still way cheaper to recycle what we have on our surface before we run out of mines or grab stuff from orbit.

[1] https://en.wikipedia.org/wiki/Bauxite