Not all problems are "work" vs "doesn't work".

We're not talking about making a calculator that can't calculate 1+1. This might be a website that's a bit slow and janky to use.

25% of users go away because it's shit, but 75% stay. And it would've too much effort to push the jank to zero and retain a 100%.

A website that takes juuuust too long to load still "satisfies requirements" in most cases, especially when making loading instant carries a significant extra cost the customer isn't willing to pay for.