There is another factor with enterprise software - people build workflows around it that are business critical (think checklists and HOW-TO guides), and taught to folks that just want to turn the crank and get things done, not mess around with the latest changes (in general).
UX changes (usually what people mean when they say ‘usability) are problematic because they often require disruptive changes, retraining people, and breaking someone’s business for awhile if they can’t know this is coming and stage it out properly. That is a good way to lose customers.
Performance improvements over unlocking some major business area with a feature are not as high priority - because an extra .5% in cost to an existing customer is usually not as important as unlocking another 10% of sales.
Over time it can of course kill the product if not addressed. It’s easy to see how the incentives lead people there though.
And for an enterprise, they already pay people to do things they aren’t excited to do every day - why should they care the software is motivating when people already clean toilets, deal with retail customers, and mop floors without any of those being exciting either? As long as it works, it works.