It's still very cumbersome to type a search on mobile, and having to type a url first or launch another app is almost half a minute more. That alone drives people to google. The rest is just google taking advantage of users that have fallen in its trap. IMHO, if these major companies like expedia stopped going after mobile aggressively , that might inconvenience users enough so that they would switch to use a desktop for their travel searches of deals, where they have much more control