Like all enterprise software vendors their customers are the ones who buy it, not the ones who use it. In almost all cases the person signing the cheques will never experience any of the issues themselves.
This happened like 2 years ago at least, every update to Jira makes it slower and less usable, I have given them this feedback many times, and I suspect I am not alone, and they simply do not care. Until they see subscriptions drop, they will do nothing, they are like Rational Software or CA when they hit the big time and started buying up all their competition.
You and I must use a very different JIRA.
But then they're never going to look at the UI for Jira either because they're too busy for that.
(Slack is another good example. Slack is "just" an IRC client with better emoji/GIF support. But I'll be damned if Microsoft Teams doesn't _really suck_, even with the benefit of knowing how Slack does everything. Good software is hard and takes work.)
Trello was the counterexample: it implemented less than 20% of Jira's features and was all the more useful for it. (thus Atlassian bought it and have started ruining it with bloat).