There are people who aren't influenced by what is popular or what everyone else is doing. Some of us run away from that sort of thing. So there will always be a market for games like this... and mostly single player affairs.
Also, with skylines, it really doesn't matter if you win or lose, its just about having fun. Sim city was the same originally. It was just a plot to have fun in. I sort of hate games that don't let you be free.
Luckily not all games are big dumb action games/shooters though in some years its hard to find anything else.
Tropico is a an edge case, yes, you build a city but its also a country as the entire map is just you. i feel its closer to an empire builder but its more weighed on construction than most other games like Anno that is also in a similar category but at the opposite end. Anno is more like Skylines in that you have multiple sites, but lets just ignore supply chains... i did say Anno was at the opposite end. Some games just ignore supply mostly, others concentrate on it.