I firmly believe that every language has an equal proportion of spaghetti code to clean code. The only factor that might screw with this is how much a language is used in industry, which I’d expect raises the ratio. However, there’s plenty of hobbyists writing spaghetti code too so I don’t think even that factor has much effect.
Okay, I’ll grant you brainfuck… As for assembly, I don’t think it’s inherently spaghetti. You can split it up into functions just like you can with an actual programming language. It’s not impossible to make structured code.
That said, I never coded assembly outside of a mandatory university course, so I don’t feel super confident in saying that. But I don’t think of it as a programming language anyway - it’s a 1:1 translation to/from machine code, and machine code isn’t meant to make programming easy or scalable.
And TBF neither is brainfuck. It was a bit of a cheeky example, but I wanted to really emphasise the range of differences between languages, and language-like things.
I have trouble believing that every language is exactly as easy to organise code in. I’ll give you that it’s possible in every language (and assembly) to organise code, but that’s far too low a bar for practical measurement. Technically you can dig a ditch with a rusty spoon, too…
If Roller Coaster Tycoon had well organised code, that was down to way more effort being expended to make it that way.