There is/was an extension that did that at some point, but it was never used (on Linux) due to poor implementation and a desire to target low RAM machines. Mac

There is/was an extension that did that at some point, but it was never used (on Linux) due to poor implementation and a desire to target low RAM machines. Mac's backing store implementation was quite heavily optimised - macOS can do on the fly memory compression and the window server uses shared memory to obtain the window bitmaps.