I am aware about the fact that bathroom tiles and ceramic tiles manufactured to spaceships thermal shields differ so much that those have nothing in common. details matter especially because you seem to know for what the tiles are about..

and btw the tiles aren't for ascending at all, they're needed for descending only and just to make spacecraft reusable, nothing more.

and btw it would be realistic to discount the capital costs to the end price. for example if I pay 5 million dollars for a oil rig and I get 40 cent discount per fuel liter for that and I drive 10k km per year with 7l/100km average consumption for my whole life, is it worth it?

spoiler: I would save 18 million dollars in total, but with 5% interest the discounted price spent to oil rig would be 98 million dollars.... so in the last line there is only one number: $-80000000 (sorry for non-american marking of that)