This is true for more than RoR. ASP.Net MVC has the same issue, but Microsoft headed that off by creating WebAPI, which is a better fit for the single page app

This is true for more than RoR. ASP.Net MVC has the same issue, but Microsoft headed that off by creating WebAPI, which is a better fit for the single page applications. Not that you couldn't do everything in WebAPI in MVC, but MVC was more of a website framework, while WebAPI has no rendering capabilities.