Its true there really isnt a target market for launches on the scale Starship hopefully will allow. Falcon/Falcon heavy seem like they would be capable of vacuuming all of the "orbital launch market" into the hands of SpaceX if they focused on that. This is of course ignoring the catchup factor. I expect F9 will have competition at some point and there is a good chance they will find ways of iterating on the "barge landing" model that (may) be able to undercut SpaceX. Industry leaders never stay on top for long if they aren't innovating themselves to maintain their lead. I have always seen the speed and force behind Starships development as that private company mindset of not resting on your laurels applied to a sector that never has seen it before.
Thats a side point however. If i recall past criticisms, I think the point you are trying to make is that it doesnt matter how advanced or fantastical your product is, if no one will buy it it doenst matter. Which of course you are correct. I dont think it is correct to assume "there currently is no market" means "there wont be by the time Starship becomes operational." I have a much more muted timeline for that of 4 to 5 years (at least) to iron out the all the technical issues they have not even discovered yet and that for me is just "working unmanned launches with payload." Not refueling and certainly not manned flight. But lets actually look at economics:
SpaceX cannot maintain Starship as simply a "billionaires toy." No matter how rick Elon is or manages to become, a business needs to be turning a profit and that means customers.
Proposed customers/revenue stream at various times:
P2P personnel: not happening. Certainly not happening to support Starship with the timeline i suspect will happen
P2P cargo: Less insane that manned p2p, but sill enormous engineering challenge, regulatory challenge (sonic booms are no ones friend) Most importantly however, I dont see it as a multibillion market. Cargo ships are more efficient and in mass transport, efficiency is key. Worldwide air cargo per year is ~60 million tons while worldwide seaborne cargo is ~11 billion tons. What fraction of the 60 million on airfreight will be willing to pay at least 2 times the price for their cargo to be faster? Unknown, but I would hazard if you dropped a fully functioning starship with p2p capability into SpaceXs hands immediately they would struggle to do 1 million tons of cargo a year. Might supplement Starship operations, but I dont see it ever managing to become a main business model. The only reliable customer I see would be military.
Mars base: To have an economic mars base in the near term, Mars would need to have something worth exporting. It simply doesn't. If someone *else* manages to set up a functioning colony, then there becomes a market for transferring supplies. But that is dependent on someone else floating the cost of actually building and supporting the colony.
Moon Base: Most of the same problems with Mars, except it becomes much more likely to find someone else to foot the bill. Especially when you broaden it out to beyond US government as the possible customer. Russia and China have both made talk of founding a lunar colony. If regulations change to allow SpaceX to support international efforts like that (and those countries also go thru with their plans) I could see cargo runs becoming a viable income stream for Starship. I dont see even China and Russia combined managing to fully support a sizable moon base with their existing launch vehicles and I could see them using starship as an interim solution while they develop domestic capacity. Likely? probably not due to politics, but its at least possible. Another possible country would be India who could see an operational starship as an opportunity.
While I understand the sentiment, you still need to pay for the ticket. Either you, or someone else. If you are going to mars and expect more than just to be dropped down with a finite life support and then die, the bill becomes even bigger. Again, as rich as some people are, in order to support a permanent human presence anywhere off world, there needs to be economics considered. Motivations do not make ability irrelevant.
So now lets go to ones that I think might actually work:
Starlink: this obviously is the fastest to become a reality . Launch cadence does seem to have been a limiting factor for rollout and telecoms has the market to bring in the necessary billions. Will it be enough? Probably not long term, but will hopefully be enough to float the R&D costs for a few years. And maybe not just for Starship. As many of you have pointed out..
And on the list of possible market which i wish i could go into more detail on but this post is already far longer than I thought it was going to be
Space Mining: since transport is a big issue I dont see how a monumental revolution in transport capacity will be irrelavent. Will it be enough? Certainly not on its own, but it at least is a possibility.
Space Manufacture: This is an even bigger what if than mining, because its something that we seriously have no idea what is possible. Lack of transport in this area has made R&D into zero g manufacturing nearly impossible. There have been no real advantages found, but to say we have enough data to eliminate the possibility that we will find some even in the next 5 years is just wrong. We just dont know.
I see the most likely customer for many starship launches within the next 10 to 20 years is a commercial research base either in low earth orbit or lunar orbit looking into manufacturing technologies. Probably funded by the semiconductor industry giants of NVidia/AMD/Intel or thier successors. They have the cash flow and existing techniques are rapidly hitting their limit for increasing circuit density.