RetroGaming

It's probably not because it's sucks. It's because they're trying to perfectly replicate an existing target. They have to read the assembly, digest it, then create the identical solution in C++. If they were just creating a new game, it likely would be much faster.

#include <iostream> // because writing to the console is not included by default.
int main()
{
std::cout << "C++ is simple and fun ... you cretin";
return 0;
}

I had a machine language course in uni, parallel with a C++ course. Not a fun semester to be my wife, or a relative of any of my classmates. Best case our brains were in C++ mode, worst case you needed an assembler to understand us.

And yes I know my code format will piss people off, I don't care, it's the way I write when other less informed people don't force me to conform to their BS "Teh oPeNiNg bracket shouwd bwee on teh sam line ass teh declawation"

You are very unlikely to write assembly that is more optimized than what a modern compiler could produce for anything longer than a trivial program. I don't know if it made sense at the time of the original RCT, but OpenRCT would definitely not benefit from being written in assembly.