There's definitely an incentives issue here. Product just wants more features. I feel like product managers (bad product managers at least) need a countervailing tendency in the form of a resiliency manager or something.
Actually, a great way of managing this sort of stuff is implementing error budgets and SLOs. If you app isn't performant, the next sprint is dedicated to fixing issues, et cetera.
If the business wants a stable and well working application, prioritise it as part of regular dev work. As a dev this is certainly not my problem.