This was the case in early days when people did not understand on what protocol bitcoin really works and how. But as soon as bright minds started coming up then they started creating the copies of bitcoin algorithm which manipulated the working methods on blockchain. Then smart kids came up with idea of implementing their own blockchain over the traditional one and thus created all new ERC20 protocol on which most of the altcoins are lurking around.

However, though that is the case I dont think bitcoin is getting very much hampered with the altcoins market. I mean I know that whenever their is mass dumping of the altcoins then the money must be going into the bitcoin only and nowhere but have you checked or observed the market recently It is going all exactly in promotional way. Whenever bitcoin is falling the alts falling and vice versa. In general we are not sure about your statement and neither we can say that it doesn't affect it.