- you get a slower first load (cannot progressively fetch resources as they're needed)
- can't reuse a stylesheet, script or image on a different page (each has to have their own copy)
- can't cache commonly used files
- can't make granular changes to specific parts of the code. user has to reload everything each time.
- can't set a proper content security policy
And many more! It's cool for a tiny demo but for anything serious you wouldn't want a single (extremely ugly) HTML file.
- you get a slower first load (cannot progressively fetch resources as they're needed) - can't reuse a stylesheet, script or image on a different page (each has to have their own copy) - can't cache commonly used files - can't make granular changes to specific parts of the code. user has to reload everything each time. - can't set a proper content security policy
And many more! It's cool for a tiny demo but for anything serious you wouldn't want a single (extremely ugly) HTML file.