Didn't old-school mainframes with discrete transistor CPUs use time-share mechanisms and charge enough for the time that people cared about minimizing it? UNIX

Didn't old-school mainframes with discrete transistor CPUs use time-share mechanisms and charge enough for the time that people cared about minimizing it? UNIX goes back 50 years, but IIRC there was a substantial amount of "pre-history" before that too. What's old is new again.