It's one potential way of looking at it. By the same token, you also would expect that with more services moving online as opposed to in-person—as has been the case with the CRA, notably—there would be efficiency gains, especially with answers to questions from Canadians. The number of FTEs per million population would not necessarily be the same in 2022 as it was in 2010, but there may very well be other factors at play. So, yes, that's potentially one good explanation, but there are other factors to consider as well.
On December 1st, 2022. See this statement in context.