The fact they are not currently even close to profitable with ever increasing costs and the sobering scaling realities there is something you could consider, and if you do believe they are sustainable, then you would have to believe (in my opinion, unlikely scenarios) they will somehow become sustainable, which is also a conjecture.

Seems a little unreasonable to point out “they are still around” as a refutation of the claim they aren’t sustainable when, in fact, the moment the investment money faucet keeping them alive is turned off they collapse and very quickly.