Starship derived vehicles would not count. I will take a liberal view of what might be considered Starship-derived.
Any rocket system that can travel at least 4000km at hypersonic speeds on a (mostly) ballistic trajectory would count.
It must be a regularly scheduled flight (at least weekly), between two locations, that anyone could buy tickets on, rather than a demonstration flight.
After 2040 or Never will resolve YES at the beginning of 2041.
1,000@ScipioFabius provided the business case is there, I feel like this could scale up relatively quickly. Falcon nine turnaround has easily dropped to match customer demand. Provided someone gets it working on some fixed route (say, SF to LA) I would put decent odds on it running weekly within 5 years.
That said, I still think it's overall unlikely to happen. Also "scheduled" may end up a tighter bound than weekly - it's much easier to imagine this operating more like a private jet.
@spider Yeah, the business case for earth-earth rockets is a big IF on its own, and if it does operate, the private jet kind of thing is more likely I think, unless someone finds a way to get the prices really low. The more likely scenario for a scheduled business is I think earth-orbit case where its paid by companies for workers, but that is much more off then 2040.