I would love to meet the guy who started the myth about a city having to do with a population of 100k. He's probably laughing smugly at his computer, alongside the guy who posted about the canceled Ger wedding.
I'm not sure what you're saying here, once you hit a certain threshold you can convert your township to a city which gives the locals more power which usually benefits the local residents, on the other hand a city can impose local taxes so it's not so exciting,
by becoming a city it gives you more flexibility and more responsibilities as well