Definitely, and I'll never try and make the argument against that. However what they did was definitely a significant improvement on these pre-existing translation layers.

Linux gaming can be clearly defined as pre-proton and post-proton because it was such a huge improvement to the experience (one-click installs, large number of support in games, gaming via proton counting as a Linux sale in publisher metrics, etc)

And I'm speaking from personal experience, before proton I had a hard time getting pretty much every game I tried to play working on Linux (and tbf a large part of this is probably me fumbling the installation but I'm not an untechnical person either, so I'm sure this was the experience for many)