Why don't the "short permalink" URLs use a shorter domain, and why aren't the decimal IDs converted to a higher base?

Question

I was going to share a link to one of my SO questions when I realised that the actual question URL (without the human-readable title) is the same length as the "short permalink" URL after my user ID has been appended to it. I imagine my user ID is appended for a good reason, however the outcome isn't a very "short" URL. Why aren't the permalinks using a shorter domain, and why aren't the IDs within converted to a higher-base number system to actually shorten the URL?

As an example, this question's actual "short" permalink is:
http://meta.stackexchange.com/q/170533/211113

A 45 character URL isn't very short. I imagine this could quite easily be shortened to:
http://meta.exm.pl/29A25/338A9, or simply:
http://exm.pl/6/29A25/338A9, where "6" here could be an ID relating to meta.

Answer 1

Probably because making those URLs extremely short adds complexity to the system and makes the links harder to read, while not providing any clear advantage.

Extremely shortened URLs are usually less useful than their expanded versions, because you don't see where they are pointing. If you want that effect you can just use any of the countless existing link shortening services.