> pretty slow or very challenging to implement in pure HTML/CSS
That's the heart of it, isn't it? It's challenging.
At the core of modern web development is the attitude that developer convenience trumps all.
The software is free after all. (The thousands you pay in bandwidth and hardware upgrade costs to keep running their bloatware doesn't count because none of that goes to the web developer, and is therefore irrelevant in their it's-all-about-me worldview.)
That's the heart of it, isn't it? It's challenging.
At the core of modern web development is the attitude that developer convenience trumps all.
The software is free after all. (The thousands you pay in bandwidth and hardware upgrade costs to keep running their bloatware doesn't count because none of that goes to the web developer, and is therefore irrelevant in their it's-all-about-me worldview.)