Yeah, exhausting resources on the moon is a valid concern, it could be an invaluable, even necessarily asset to furth space exploration, but should probably be viewed as a stepping stone to something more sustainable, possibly asteroid mining, capturing comets etc.

I certainly glossed over that in my comment because it was already getting longer than I liked and I kind of wanted to focus on just the cost of getting things into space, but it is something that needs to be managed carefully or we lose an important foothold we might need to take the next steps.

I'm certainly no rocket scientist or astrophysicist so exact details are a bit over my head, and to be clear I'm talking about long term goals that are decades if not centuries out, but I'd kind of imagine that the ideal situation would be something like using the moon to get enough fuel to go mine a few comets and then use the ice from those comets to support future missions instead of getting it all from the moon.