Because it was simple and the rest was very complex.
In fact, only assembly language for some CPUs was as simple as basic (now, it's not really the case anymore, although asm basics are simple, stuff often gets complicated with special registers and special opcodes doing magic)
Many languages today as simple and relatively sane, like, say "python" ;-)
(now the other reason why I like python is because while you don't feel limited with it, it _forces_ people to code half readable, half decent stuff. They got a good balance)
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To iterate on what you said:
Because it was simple and the rest was very complex. In fact, only assembly language for some CPUs was as simple as basic (now, it's not really the case anymore, although asm basics are simple, stuff often gets complicated with special registers and special opcodes doing magic)
Many languages today as simple and relatively sane, like, say "python" ;-) (now the other reason why I like python is because while you don't feel limited with it, it _forces_ people to code half readable, half decent stuff. They got a good balance)