I think the immediate reaction from people invested into Bitcoin would be negative, when they hear that some new Alt coin or "Blockchain" based technology was launched. You immediately think that money will flow away from Bitcoin to these Alt coins and Bitcoin will lose investors.
Could a new coin attract new investors to the whole Crypto currency scene, that would not have invested, if it was not for this coin?
Let's say for instance "Mc Donald's" launch a new Alt coin, called "McCoin" and Billions of people starts to buy and sell these coins. What would the natural spinoff of this be? I think "increased awareness" of Crypto Currencies. A percentage of these people might start to trade other Alt coins or Bitcoin as a result of this.
Do you think this is Good or Bad for Bitcoin, when this happens?
Most new people when they learned about BTC they saw the price and felt they missed the train. New Alts coming up starting very cheap (including ICOs) and constantly rising in value is what brings people in crypto. Almost none sane would invest in an overpriced asset at its ATH.
So imo alts are actually helping BTC by importing more people into crypto.