If it were not for copyright and copyleft software licenses there would be no open source software of any significance.

All these projects only took off because people were forced to contribute back. Want an example? Look at the state of opensource boot firmware on x86. The "open source" version heavily relies on proprietary firmware blobs and the only actual open source alternative had been heavily ridiculed for pursuing that goal and trading basically any significant compatibility for it.

Copyleft licenses make software basically self-regulating utilities. You can draw power from the grid and in return help finance it for everyone else, or you could build your own power plants.

You can draw excellent pre-made software and tooling from copylefted repositories and contribute back, helping to make the software even better for everyone else, or you could build all of it yourself. Or, you could put in the work to replace all major copyleft software with non-copyleft versions, eventually gaining the ability to pull up the ladder behind you.