Now granted, there is still a very small probability that this will happen, but even if I don't become a millionaire, I at least get to see John McAfee eat his own dick, which should be great fun.

You didn't hear that McAfee backed off his prediction of 1M by the end of this year. He called people gullible for believing him. But what many people forgot was that he made an earlier 500K prediction and then upped it to 1M because he was expecting 5K at the end of 2017, but got 4x that so he said "I'm being conservative, and will stick to 1M when the model shows 2M".

I think I know why he really did this. He wasn't happy with the ossification of the protocol and the fact that it offers little privacy. I don't think he wanted to support a protocol that if not changed will eventually lead to book of Revelations consequences. He's been talking very favorably about Monero and other privacy coins and is now calling bitcoin a dinosaur.

The truth is that in Dec 2017 transaction fees on chain were approaching and sometimes exceeding $100. After segwit total adoption, this now will happen when bitcoin reaches about 80K. So at 1M bitcoin, you're going to need at least 1K for transaction fees on chain. I was wondering why McAfee didn't mention this so either he didn't know (that seems unlikely) or maybe he was placing his hopes in LN.

There's also the issue of the segwit donations attack that @anonymint writes about in his blog. I've not seen the game theoretical math that makes it more profitable for miners to cheat at the block halving, but I cannot discount it. If one can roll back the protocol so that only P2PKH's are recognized, then P2SH's can be spent by anyone finding a block. If/when this happens, this will cause the price of segwit coins to tank while legacy bitcoin skyrockets in price.

Fungibility issues are a problem as well because newly mined bitcoin goes for a premium. As the taint spreads, some bitcoin could be valued very differently than other bitcoin. Keeping a close watch for a couple of months after the next halving.

PS - Segwit coins are addresses that begin with "3" or "bc". If you have "1" at the beginning, this is legacy bitcoin. @anonymint says that the segwit taint on legacy coins will become a problem when spending (after the miners are done seizing all the segwit donations).