Those programs claim that they can "restore" the original master, which means going back to it just before it started to be over-compressed. So it seems to be snake oil, then? That's the problem with newer music, not the older masters available.A portion of the signal that got clipped is lost data. Nothing can get back lost data.
It’s a similar issue with compression. There is no clear way to find out what compression settings were applied based only on the resulting signal. Compression tools have a variety of settings after all. Software trying to reverse compression or correct clipping are really guessing and making up new signal with the hope that it’s going to be more enjoyable. Those are tools for subjective preference, not actual restoration of data because said data is usually lost for good.
For dynamic compression I would personally leave it as is. For clipping, if it’s audible then it probably sounds quite bad and a declipper seems like the way to try and make it listenable again. I would still first try to find a non clipped version if it exists(older master?).
I’m not sure about the meaning behind vinyl losing dynamics when transfered to CD. Digital recording from a turntable sounds the same to me as the turntable itself. Vinyl allows less dynamic than CD anyway. The only reason why vinyl would have a lot of dynamic is if the needle turns into Tony Hawk and uses the bumps on the vinyl to take off.
Maybe I got a bit confused with the vinyl part you told me about, a sin of youth/haven't had one in my hands yet, only CDs. I guess a wave of rabid audiophiles will jump after this last thing I said.