Enterprise software development and design budgets are spent on:
You could maybe say that 2, 3, and 4 are all just “maintenance” but they each have their own challenges and optimizations.
The art is in balancing your budget to optimize for growth or engagement.
When it comes to engagement, Grumbling is the beginning of the end but responsiveness to UI problems stops grumbling in its tracks.
In enterprise software responsiveness to UI problems surfaced by your community of users is the key to user satisfaction. This type of responsiveness is so rare that it can be a competitive advantage.
Meeting the requirements of key stakeholders, whether or not they align with your strategic business goals, is a cost of doing business. The trick is to do this as cheaply as possible and without clunkifying your product.