I think softball coaches understand that once they hit the regionals, they will need more than 1 arm. A couple of years ago, Florida State relied heavily on Burroughs to win the WCSWS, but they wouldn't have been there without Kylee Hanson's help.
Garcia started every WCWS game for UCLA in 2019. I'm not disagreeing w/ your premise, though, just pointing that out. Garcia and UCLA might've been even better if UCLA had a second option closer to Garcia's level and allowed her to be fresher. In 2002, Jennie Finch ran out of gas in the final inning of the c'ship game after being Arizona's sole pitcher all week and pitching 11 shutout innings the day before. (I was just looking that up; my memory is not that good.) fyi, you're thinking of Meghan King at FSU, as Burroughs had graduated after a nice career.