I'm not saying you are wrong, I just don't understand your reasoning.
Why do you think that Altcoins will boom again after the BTC Fork?
Mass adoption! The only thing holding altcoins back right now is because everybody wants bitcoin to get the extra hardfork coin. Once that's over, investors will pour back in to the altcoin market.
Or maybe people are hedging with alt coins now, ready to jump back into bitcoin after the fear of the fork goes away. People don't need to go through bitcoin anymore. Bitstamp, Coinbase, Kraken and all the major bitcoin exchanges have fiat - alt trading pairs already.
If the market was hedging with altcoins, bitcoin would be going down vs altcoins up not the opposite like what is happening now. I can tell you right now, that all the big wig bitcoin investors I know want that forked coin. The market has learned from the the last fork, that a split is not to be feared anymore. It is to be embraced! Free coins = more money! They aren't getting back in to alts until after they get there new coin.