We had those (Flash, Shockwave, Java Applets, etc.), the browser won.

Nobody is going to win over browsers with an opinionated batteries included application framework.

Those all had major issues. All of them were constrained to a browser environment, the first two were proprietary and full of security holes, and all of them had a reputation for causing browser or even full OS crashes.

I wouldn't say that any of them were particularly "batteries included", either. Flash was probably closest but still left a lot of legwork to the developer.