If you have a deep history with gmail then that could make it harder to to replace. It’s very true especially if from important positions you participated in, along with multiple accounts on it which I like to call leaving eggs all in one basket since they are all reliant on that account.
For people who arent quiet as invested in that, and just use it casually which is a pretty big percent could easily replace gmail with nothing to lose and those are the type of users I was thinking about when writing up this post. But I can agree with what you are saying here and that you have a good point.