Because learning Flash was easier than learning HTML5. The tools and scripting were incredibly easy. No one has made a good easy-to-use HTML5 editor. As complex

Because learning Flash was easier than learning HTML5. The tools and scripting were incredibly easy. No one has made a good easy-to-use HTML5 editor. As complex as Unity can get, it's a better option than learning HTML5 these days. I hope one day a powerful low-friction successor to Flash will appear.