What you have been saying is not true and some altcoins can still able to get a huge pump even without the help that must have come from the bitcoin. I do agree with if it's not all of top coins are getting their price from the use case but it's coming from the speculation.
Yes, I see that too, now Altcoin doesn't need the help Bitcoin for Pump. There are some coins that can Pump themselves without the help Bitcoin, This is purely due to supply and demand, so if many people buy, the price will go to the moon. Today I see the price ERT going up drastically, reaching over 150%.