There are a few problems with OOP. The one that bothers me the most is that there is immediately boilerplate complexity. How is this bag of data addressed? What does it behave like? How is each piece of it read and written? Now you need collection generics. There’s complexity everywhere, and it’s expensive. It hampers concurrency, and doesn’t work on GPUs. What do we get for it? Implicit control flow, and it isn’t even clear to me that this is a benefit let alone worth the costs. Any time performance is remotely a concern, object orientation should be the first thing removed.