I also agree with you, if bitcoin is bullish, there are a lot of Altcoins that has increased by more than 10x. It is not clear at this point which altcoin has any sign of going up, as bitcoin's price is not bullish yet. The bullish moment is always awaited by cryptocurrency enthusiasts, before the bulls come, traders should collect some of the coins that have the most demand to prepare for a 10x increase when the bitcoin price is bullish.
I think it's pretty obvious because people who are patiently waiting for Bitcoin bulls will always win in the end because they try to collect more good coins during periods of downturn in the market. So the profits can be very large if all the coins they buy at this time experience a very good price increase.
Majority of the cryptocurrency follow the growth pattern of bitcoin. So, when the bitcoin market turns bullish, automatically the same gets reflected over the altcoins. This assure booking of very large profit.