[texaslonghorn5]

When you're serving someone an HTML file are you serving them the exact copy on your file system or do you ever use templates? Do you ever pull info from the database? If so, can you see why this is slightly different from directly serving a static pdf?

Also note that you'll often see a PDF generated on the fly with a long, difficult to parse URL.

Take up your second point with the W3 or whatever, to be honest if tlds weren't so important for phishing and whatnot it would probably be fine. I think some browsers have started doing that anyway. You overestimate how tech savvy the average user is, and by extension you overestimate how much the average user can keep track of all this complexity. Do you think most people have heard of .info or .xyz?