Newsflash: Almost all of the travel sites you've heard of are owned by Expedia or Priceline. Priceline couldn't buy Expedia because it would get killed by antitrust concerns. Expedia also owns Travelocity, Orbitz, Hotwire, Hotels.com, VRBO, HomeAway, has a majority stake in Trivago, etc.

Basically the only big travel sites not owned by Expedia or Priceline are TripAdvisor (previously spun off from Expedia) and AirBnB.