Saying that 6502 is useless is a bit harsh- I wouldn't call it an employable skill, but it's great for hobbyists who are into retrocomputing (like me).
You could deep dive into x86_64 or ARM, but in the general case you would never actually code in those (i.e., most folks trust the compiler) unless you were writing a driver or writing something with crazy performance like MenuetOS.
You could deep dive into x86_64 or ARM, but in the general case you would never actually code in those (i.e., most folks trust the compiler) unless you were writing a driver or writing something with crazy performance like MenuetOS.