The memory model is flat enough. The problem with the memory is, you only have about 200kB traditional RAM. But then, you have 8MB of PSRAM. But it requires strict 4-byte alignment, and is noticeably slower.
What makes traditional OSs difficult on this platform, is the lack of memory protection. But I am a simple man, I am not writing an OS, all I wanted was a usable shell and an apps installer, so I made that work.
Just like MS-DOS and CP/M did great with such hardware constraints.
I still think many don't understand how much is possible with a plain ESP32.