This may be true, but the C64 booted into a BASIC interpreter with PEEK and POKE commands, making it possible to read and write to all of the system's memory, including mapped IO ports, from the command line. Plus, monthly magazines like COMPUTE'S Gazette offered in-depth tutorials on just about every sub-system, from audio to video to disk I/O. System-level programming was incredibly easy on the C64 -- I was doing it as a teenager, whereas I have yet to write a device driver for a Linux PC.