The price will go down another 86% from here then, hello 3000$ per btc.
Bitcoins price always stays the same, always was the same and will be the same. 1btc = 1 btc
How do you sell bitcoin for fiat ? P2P fiat on/off ramp filled with fraud and scams. No normie in their right mind will use p2p
Adoption in the underground happens slowly but organically. Once people realize that their fiat is melting like ice in their hands and they see every craigslist sell having a Bitcoin option and they see their friends splitting restaurant bills with lightning etc. you get a wallet app and just transact naturally.
People using the best currency available to them is just very natural. It just happens organically.