Why would anyone put themselves through that if they didn't have to? There is the tale of Allen hand coding the bootloader in machine code, but that was because he was on the plane to give a demo. Otherwise, all of the tales I've heard of the development of BASIC involved a mainframe. Hand coded assembly was certainly conceivable, given that terminals weren't exactly everywhere back in the day, but even a basic assembler does more than the straight translation of instructions into opcodes.