I think one of the problems, is that many people do URL's the wrong way. And I can not blame them, as writing information in the URL at least used to give better ranking in search engines. Most SEO people will say that the URL is important! So like many other problems with the WWW, we should blame Google :P

One example on good URL's are HN: https://news.ycombinator.com/item?id=9637215

It will not help ranking on search engines, but the URL will hopefully never change.