This isn't something I'm completely sure of, but can BTC go down while Alt go up? Wall Street may get on BTC but not so much on Alt. Cryptos can be seen as a safe heaven asset akin to gold. Wall street may have to sell but the buying demand will also be high.
http://www.visualcapitalist.com/comparing-bitcoin-ethereum-cryptos/

BTC has been massively loosing its influence over crypto space and it could stop being the moon that drags down everything. I'm not 100% sure on this. But I'm willing to put my soul behind your Melt Up followed by crash theory. Hats off to your call. I think you nailed it.