Many cases I knew, people would have several repeaters and extra routers to extend coverage in big houses, and not set it up correctly in PA/Bridge mode, so peripheral network devices would be locked behind in a separate NAT’ed subnet.
[1] Not something we'd /normally/ do, but when that was going on... You just had to get people working.
If users can't set up routers and extenders properly, that may say more about the designers of the routers than the people using them.
I'm nominally an expert user, but a lot of these products make me WTAF regularly.