This is not the reality when you go into most organizations. It may have started like that but a few cases of "just one more call" result in the client making a load of calls at startup followed by many others when user navigates to a detail screen. It probably caches a few items, but many others are not cached appropriately.

This is what the vast majority of developers are facing. Be thankful, if you don't have to clean these messes up only to move to another team to repeat it. It happens naturally because of the tension between shipping things and finding enough time to properly optimize.