I think this would have been true in the past, but it may be changing. Google are fast degrading their maps UX as part of their maps monetisation efforts, to the point that backlash has even reached normal users. I was listening to a very mainstream commute-time FM radio talkshow yesterday that brought up Google Maps' UX degradation - that's an extremely non-tech audience. I can see a new space growing in the market for people wanting a Google alternative for reasons entirely removed from ethics.

In addition to all of the above, Maps.me has had a pretty ample userbase for a long time now - while it is technically an open-source codebase (to the extent its even been forked & put on FDroid), its privacy policy & general Russian links of the company behind it still leave a lot of red flags for your typical OSM users.