Nothing about bitcoin is sustainable, exponential energy waste, new asics needed every 2 years, no guarantee that price covers cost, competitors with cheaper fees and faster performance with just as good security.
"just as good security"---no, not with regard to attack cost.
why should there be any
guarantee that price covers cost? is that true for gold miners or any other commodity producers? of course not, because that's not how free markets work.
What anti-Bitcoin newbies like Kahos77 fail to understand, or avoid to understand, is that Bitcoin's model has been very sustainable. It's already right there in front of their eyes for 10 years.
More miners => more secure => more confidence => more users => higher price => more miners => ...