Netflix used to be a unicorn at one time. It didn't primarily expand the rental market to become a unicorn, it rather rapidly destroyed Blockbuster and thousands of other rental stores by providing a better service. If it was primarily expanding that market, Blockbuster would still be around. Today it's not expanding total TV viewing time, it's proceeding to harm cable, tv networks, traditional tv programming, ESPN, HBO, etc etc.
Tesla - also once a unicorn - isn't expanding the automobile market. They've been directly taking sales from BMW, Mercedes, Porsche, Lexus, Audi, etc. The success of the S sedan is coming out of the high end luxury car sales segment. Their 3 sedan will continue that process. That's why those other companies are so freaked out by Tesla's arrival and relative success. If Tesla were primarily expanding the market and not stealing market share, the competition wouldn't be reacting the way they are.