There is nothing medieval about Tamriel.
There are a million little things about Tamriel that clearly make it far more advanced.
The ubiquitous use of printing for other things than religious texts. Advanced glasswork such as the clear glass panels seen on the display cases in oblivion. The architecture of the cities. The very way their society is layed out.
All in all they are far more akin to the renaissaince than those boring middle ages.
And that is even ignoring the fact that Tamriel is not Earth and has vastly different natural laws wich means they will never have technology.
The point brought up before is an excellent point.
Medieval has absolutely nothing to do with TES.
Actually it's a horrible point. The Elder Scrolls is a Medieval Fantasy. Medieval because it relies on the sword and sorcery formula and fantasy because of all the things you mentioned.
The entire concept of the game is based on ideas taken out of medieval fantasy media, be it books, movies, comics, what have you. Sure it's a separate world, but it's not a real world, and it is a world completely derived out of the game developers wanting to make a medieval fantasy.
I don't care if Tamriel isn't earth; it's a made up world that is completely derivative. If you ask any of the developers what time period they draw most of their inspiration from, can you guess their answer? If it's not the medieval period I'd eat my boot.
This of course doesn't mean they need to stick strictly with whatever was the norm in the medieval times, because the whole fantasy section gives them leeway to do whatever the hell they want with the game. But to completely ignore how the game is a derivative medieval fantasy, like almost every other rpg on the market, is ludicrous and and implies some cognitive dissonance.
Summarily I am saying that Skyrim's setting is extremely comparable and derived from the middle ages and medieval times, especially the Age of Vikings. To ignore this is as I said before ridiculous. So when coming up with ideas and projections for the game, this is the time period they will be drawing most from.