> I have found that null pointers are usually very easy to find and fix, especially since most platforms reserve the first page of (virtual) memory to check for these errors.
This is true. However, you have done these fixes after noticing them at runtime. This means that you have solved the null problem for a certain control + data state in code but you don't know where else it might crop up again. In millions of lines of code, this quickly becomes a whack-a-mole.
When you use references in Rust, you statically prove that you cannot have null error in a function for all inputs the function might get if you use Rust style references. This static elimination is helpful. Also you force programmers to distinguish between &T and Option and Result -- all of which are so common in system's code.
Today it is safe to assume that a byte is 8 bits. Similarly it is safe to assume that the first page in virtual memory is non-readable and non-writable -- why not make use of this fore knowledge ?
> This is related to the drunkard’s search principle (a drunk man looks for his lost keys at night under a lamppost because he can see in that area).
This is a nice example and I do agree in spirit. But then I would offer the following argument: Say, a problem (illegal/bad virtual address) is caused 60% by one culprit (NULL dereference) and 40% by a long tail of culprits (wrong virtual memory address/use after free etc). One can be a purist and say "Hey, using Rust style references" only solves the 60% case, addresses can be bad for so many other reasons ! Or one can pragmatic and try to deal with the 60%.
I cringe every time I see *some_struct in Linux kernel/system code as function argument/return. Does NULL indicate something semantically important ? Do we need to check for NULL in code that consumes this pointer ? All these questions arise every time I see a function signature. Theoretically I need to understand the whole program to truly know whether it is redundant/necessary to check for NULL or not. That is why I like what Rust and Zig do.