The online travel agency business over the last couple of decades has largely been built around selling hotel stays. But in 2019, there will undoubtedly be an acceleration of the drive to diversify their core businesses not only into apartments and vacation rentals, but also into tours and activities, restaurants, food delivery, and ridesharing.
The online travel agency future is wide open. Although it has more to do with marketing and business models than products, just consider that Booking Holdings over the last year and a half reversed long-standing practices and leaned into brand advertising instead of paid ads on search engines, and accelerated its use of the prepay merchant model over its mainstay pay-at-the-hotel agency model.
So anything can happen.