Interestingly it seems to be common for artists to try to keep perfecting their art, but very rarely is their most popular work the last one they made.

There are exceptions, notably among classical composers. Bach composed the Mass in B minor and The Art of Fugue in the last years of his life (the former completed the year before his death, the latter unfinished). They are among Bach's most complex and ambitious works, clearly made in the pursuit of artistic perfection and to eclipse all previous works (or rather, soli Deo gloria). It's debatable which of Bach's works are really most popular, but they are both up there.

Don't you think that is counter productive if you're actively trying to improve?

Maybe with graphic design, but not necessarily with acting. The death of an actor is self awareness. The last thing you want to do on stage is think about the fact you’re acting. You’re not. You’re there, you’re feeling this, this is happening. Not knowing what you look like can be very liberating.

Let your coach look at the performance and tell you what to change.

This is why Stanislavski himself, the alpha and omega of modern acting, said never to rehearse in a mirror.

I've heard, second-hand, of a friend's chef-friend back home. The chef in question is an excellent chef at a top-dollar restaurant, but he eats the simplest of meals. Bread, salami, cheese levels of simple. I heard this story around a decade ago but it has always stood out in my mind.

Being able to recognize flaws, areas for improvement, etc. are great in the context of trying to improve. Having a keen eye for these things is absolutely a boon in this context.

Unfortunately, that same keen eye makes attempting to enjoy or appreciate one's own work rather hard. Stoic as I may try to be, it would just get to me. Funnily enough, I've since moved towards enjoying cooking since my tongue is much less discerning.