> Going to completely disagree that Burst and HPC# are unnecessary and messy.

Making a managed code burst-compatible comes with real constraints that go beyond "write performant C#". In Burstable code, you generally can't interact with managed objects/GC-dependent APIs, so the design is pushed towards unmanaged structs in native collections. And this design spreads. The more logic is to be covered by Burst, the more things has to be broken down to native containers of unmanaged structs.

I agree that designing things in data-oriented way is good, but why to force this additional boundary and special types on devs instead of just letting them write it in C#? Writing burstable code can increase complexity, one has to manage memory/lifetimes, data layout, and job-friendly boundaries, copying data between native and managed collections, etc., not just "writing fast C#".

In a complex simulation game, my experience is that there are definitely things that fit the "raw data, batch processing" model, but not all gameplay/simulation logic does. Things like inheritance, events, graphs, AI (the dumb "game" version, no NN), UI, exceptions, etc. And on top of it all, debugging complications.

Wouldn't you be relieved with announcement: "C# is now as fast as Burst, have fun!"? You'd be able to do the same data-oriented design where necessary, but keep all the other tings handy standing by when needed. It's so close, yet, so far!

> The fragmentation you mention

What you say makes sense. I've actually spent a lot of time debugging this and I did find some "leaks" where references to "dead objects" were keeping them from being GC'd. But after sorting all these out, Unity's memory profiler was showing that "Empty Heap Space" was the culprit, that one kept increasing after every iteration. My running theory is that the heap is just more and more fragmented, and some static objects randomly scattered around it are keeping it from being shrunk. ¯\_(ツ)_/¯