The hardest problem with software is distribution. App developers often spend more on distribution than they earn back. This problem is solved by the web platform, however web apps have historically been less capable than native apps. With the advent of PWA’s, web apps have become just as capable as native, supporting features such as push notifications and Add to Homescreen, without giving up the reach of the web.
Codelabs, slides and more information are available from the Progressive Web Apps Training home page: https://developers.google.com/web/ilt/pwa