Never is a pretty strong word. Have you tried some of the apps on the site pwa.rocks? Flipboard and AliExpress are non-trivial examples of PWAs that do a good job. Who knows what app development will be like in 5-10 years?
As a developer I would much prefer a cross-platform way to write apps.
Have you looked into the web components spec yet? I think a combination of PWAs + Polymer (or React with web components) has a pretty good shot at easing cross platform development. It already has the support of most browser vendors and is relatively easy to pick up.