The reason this purge seems like overkill is because it's not really a response to COVID. Some of it is, sure, but many of these cuts were already planned (as said by both insiders and Bob Iger himself). It probably would have been spread out more, but COVID gave them a reason to do it all at once.
It's possible a few jobs would have been saved if Disneyland was open, but it would not have made a significant difference in either the job losses or Disney's current bottom line. They generally don't make as much money off of Disneyland guests as they do off WDW guests anyways, and with the major capacity reduction, it would have a very small effect on the overall financials.