Yes! The integration of the development environment back into the platform (Heroku actually did this in their very first product as well) is what makes replit so magical, in my view.

At Coherence (withcoherence.com) we are looking to go beyond the NewCloud companies you mention here (which are all awesome), to provide the same kind of integrated experience with Cloud IDE, CI, and Deployment all in one configuration, but running in your own cloud account using managed services. (Disclosure // cofounder)