A vast majority of full time Googlers are bucketed onto ladders that are needed in pretty much any team. Say SWE, SRE-SWE (that can switch to SWE at will), TPGM, all kinds of managers. Much of the remainder are people who should be able to do the switch, say SRE-SWE to SWE, within the grace period. Legal and accounting might find themselves in a pickle, but these don't move often.