Comment by Slow_Hand

There are tools to mitigate clipping artifacts, and tools to generate new transients for overly compressed files, but they're not a silver-bullet and the new material that is generated is more of a best guess than a true replacement for not over-compressing a mix in the first place.

These tools are most useful when used earlier in the process. Like when you just tracked an amazing vocal take, but the gain was too hot on one or two notes. The tools can mitigate some of the distortion artifacts to make it more usable. Applying these tools to complex material like a full mix will have some improvements, but at that stage there's less guarantee for convincing restoration of the record.

What I think non-professionals don't understand is that a record that is characterized by heavy compression is not something that happened at the very end with the mastering stage. It is an aesthetic choice that was made dozens of times along the way while recording, arranging, and mixing. Heavy compression is not necessarily a bad thing. Lots of amazing-sounding records harness it well. It's an art AND a craft. It takes audio engineers and producers years to do it well and with taste.