Ideas
I've got about 4 hours in the newly downloaded Skate early access and I have never once been in a server with another player. I thought at first maybe they changed it so it was locked behind one of the first missions or something but I'm even up to the mission where you need to emote to another player to continue and there's still zero players lol.
edit: Updated title
Got to around 5 hours in game on my own, over probably at least 6-7 different sessions and not once was I ever placed in a server with other players. But my mate finally jumped on to the new early access build and invited me to his party, as soon as I joined it teleported me to his server and it was full of lots of other players.
After a while he had to go so I exited the game and jumped back on to test, and I'm back stuck in a server with zero other players :( I'll update again when he's back and invites me to his party.