https://steamcommunity.com/app/386070/d ... 2960054225
Conclusion: PA is the second-most popular modern RTS after SupCom, by a slight margin.
I believe the reason for this is PA's increased complexity. Just like SupCom is less popular to AoE2, even to this day, despite AoE2 being an ancient game of far less complexity. And if an RTS came out that's more complex than PA, it would be even less popular.
Of course Ashes and Goo are less popular simply because they suck.
And don't talk to me about They Are Billions. That's not RTS at all, that's a tower-defense city-builder, as I have explained at length here: https://www.patreon.com/posts/17302456