> No program should every have variables names according to [a-z][1-9]+ pattern, except perhaps loop indices - and not even then.

What's that got to do with not breaking existing programs?

Those may be terrible variable names but they were understandable back in the 70s and 80s when disk space was at a premium and compilers only cared about the first 6 characters in a variable or function name. That's the downside of a 50 or so year old programming language: you have to worry about not breaking legacy code that did things based on the hardware limitations of that time.