I don't agree that when bitcoin hits 1M that most people will cash out, first because it's not overnight, people will sell and buy at all levels, it's like saying most people will cashout at 100k, even if some do, we will have a dip and many will buy. Second because if someone hodl until 1M, it's likely he understands bitcoin and won't sell because bitcoin has been winning proving he was right all the time and usd is dead against BTC, also adoption could be much higher. Regarding your scenario with all the ifs that I don't agree, I would consider it a failure. I would believe more in an ending like that because onchain fees got so high that no one can afford to own onchain btc.