Here's an excerpt from their October 2019 letter to shareholders. TL;DR - they're a public company and the markets told them they needed to keep growing in order to survive.
> For restaurant inventory, we will rapidly expand our recent pilots of putting non-partnered restaurants on the platform. For reasons we’ve discussed many times, we believe non-partnered options are the wrong long-term answer for diners, restaurants and shareholders. It is expensive for everyone, a suboptimal diner experience and rife with operational challenges. With that said, it is extremely efficient and cheap to add non-partnered inventory to our platform and it can at least ensure that all of our current and potential new diners have the option to order from any of their favorite restaurants now, even if it’s not the best solution. By leveraging non-partnered options, we believe we can more than double the number of restaurants on our platform by the end of 2020.
> At the same time, because we know that partnered relationships are critical to the long-term success of this business, we will be investing aggressively in our independent restaurant sales organization to support converting as many of these non-partnered restaurants to partnered relationships as quickly as possible and to take advantage of other innovations in the restaurant space, like virtual restaurants.
> For restaurant inventory, we will rapidly expand our recent pilots of putting non-partnered restaurants on the platform. For reasons we’ve discussed many times, we believe non-partnered options are the wrong long-term answer for diners, restaurants and shareholders. It is expensive for everyone, a suboptimal diner experience and rife with operational challenges. With that said, it is extremely efficient and cheap to add non-partnered inventory to our platform and it can at least ensure that all of our current and potential new diners have the option to order from any of their favorite restaurants now, even if it’s not the best solution. By leveraging non-partnered options, we believe we can more than double the number of restaurants on our platform by the end of 2020.
> At the same time, because we know that partnered relationships are critical to the long-term success of this business, we will be investing aggressively in our independent restaurant sales organization to support converting as many of these non-partnered restaurants to partnered relationships as quickly as possible and to take advantage of other innovations in the restaurant space, like virtual restaurants.
https://s2.q4cdn.com/772508021/files/doc_financials/2019/q3/...