I suspect this will change, or not roll out in many places, or users will get the choice between up-front or rental. Router rental isn't tolerated by the market in the UK or AU from what I've seen.
For AU consumers it puts even more obligations onto starlink. Only Telstra does this, that I am aware of, and their rental device comes with full remote configuration support for the duration. Telstra of course is targeting "Sell this product to your in laws and you never have to give them router support again". Starlink on the other hand, are trying the old Wisp gamble of hoping that people keep paying for their hardware long after it has paid off, which is probably a poor decision at least where Australia is concerned.
I'm saying it will change with market forces. In the US renting your router is the norm, it'll stick, and I'm sure it was a US based team that thought this would be a good idea. In some other countries it'll never get off the ground because the concept will get laughed out of the room and everyone will just use competitors.
You could argue that Starlink have a captive audience, but that's not true in most of the UK/AU at least, where high speed internet is widely available to most. Those who need Starlink probably already have it and own the hardware, their growth market will have to be homes that have other options, and those other options don't charge $10 a month for the hardware.