I played one sim day and kept checking for resort workers. Now there are sims going to the resort, and even using the amenities, but still no workers. I saw only two resort workers around all day, with MC's focus. One of them was going home, the other was idle on the other island. Both of them were low level maintenance workers, but the resort that's open, La Costa Verde, is set for high level maintenance.
I decided to close La Costa Verde and open Sparkling Sands, and see what happens. I had to quit my game at that point, but I will watch it next time I play. I'm wondering now too, if I had my sim take over Hobart's, if any workers would show up there. She doesn't have the money to do any upgrades to Hobart's, and running a resort is not in my plans for her, as she will be moving to another town in a few sim weeks. So it's not going to happen unless I do a test run that won't be part of her actual game. But I won't be doing that either, unless Sparkling Sands has the same problem. Then I might.