As consumers, most people probably only care about what modern browsers can do. As a developer, the mechanisms become front and center. Modern web development is a Rube Goldberg kluge of things glued together with duct tape. Flash was much more coherent and imposed less cognitive burden of tying it altogether.
Not just NPM - the "web" is a diverse set of APIs with various peculiarities. It's not inviting to an artist with little to no programming experience (and even with the potential to learn). That was the advantage/disadvantage of flash - closed system, one (major) IDE, one language/standard library.
