> Remember that most teams are named after their sponsor. A sponsor is not related to any city/esport. It's just a sponsor.

It's a bit more complicated than that, actually. Most of the large esports organizations (examples: Evil Geniuses, Cloud 9, Fnatic, Team Liquid) have an identity that's separate from both their sponsors and their teams. Teams that represent a single sponsor are pretty rare -- I've seen a few, but they're not common.

This holds true for traditional sports as well. A number of people will follow "their star/their player" wherever they go. Their favorite quarterback was transferred to a new team? That's their favorite team now. The loyalty isn't to the specific team - it's to a specific player or specific players.