"Most purists insist on coding things in HTML/CSS" you write that like it's something bad.
Compared to flash HTML and CSS as enormous advantages ... it's not resource hungry and is accessible if you do it right. Through you have to know your art to use the advantages.
As a kid first learning about programming flash was amazing. The ability to draw or sequence sprites together into animations and then easily stitch those together into simple games is really powerful.
I'm not saying that we should bring back flash for entire websites as was trendy for a second, but I do think we lost something special that had a low barrier to entry for kids, artists etc to create interactive experiences
Ressource hungryness has changed since flash is no more.
Somewhere around half of the last decade, we starting having Chrome and Firefox taking hundred of megabytes per tabs and totalizing a few gigabytes that put them very close to what flash used to take, maybe cpu usage is still lower though.
