I think one could make the argument that when you're producing high performance real time applications, diagnosing why your GC pauses and trying to find workaro

I think one could make the argument that when you're producing high performance real time applications, diagnosing why your GC pauses and trying to find workarounds/fixes can take a lot longer than just managing the memory yourself. There's a lot of techniques like object pooling that people use in unity because .NETs GC isn't really built to handle how dynamic some of these applications end up being.