I guess it comes down to the fact that no one gets paid to fix anything.

Visual redesign, sure, the client will pay for that.

Fixing an existing visual design when problems are reported? Nope.

And as @gwern mentioned, https://news.ycombinator.com/item?id=30961582 , the problems won't get reported.

The contract didn't include ongoing maintenance or instrumentation to detect problems. So we can't do it.