Oh! I see. I get your point mate. As I think of what you've said, I may say that's a possible way to knock down btc. If we assume that every government of all nation decides to ban the use of btc in their country but allow the remaining alts then it will surely die because the demand will be forcibly lost  And most probably the ending would be ETH reigning as the new king. Well, that's only an assumption and very hard to put in reality so gor now BTC will stay and remain on top .
It will be the same IMO because of the impression which are engraved in our minds — that alts/token was just made for Pump and Dump. Yeah! They will support it at first, create hype and other stuff but once they are do they'll go back again to the strongest coin in the market.