Just like needing to run to the city to find a potion for cure disease? Or needing to run to the city to find more arrows for your bow? Just like needing to run to the city and buy soul gems? Just like needing to run to the city to smith weapons? And so on and so on...
Why did Bethesda not just be able to one click and do all these things? Because its makes no sense, and kills immersion. But with fast travel, all the sudden its ok. Why did they take the ways to travel in Morrowind out, and not add it in Oblivion(besides carriages), and add one click travel? To make the casual gamer happy... probably
Yes, let us go back to the halcyon glory days of Morrowind, when things were so much harder and not "dumbed down" for those pitiful "casuals".

OMG! I'm out at a dungeon, and I desperately need a Cure Disease potion! Drama! hardcoe tension!
...oh, wait. No. I Mark (with spell, scroll, potion, or item). I Divine or Almsivi Intervention (with spell, potion, scroll, or item). I then take various mass transit options (strider, boat, etc) to the town or home of my choosing, picking up whatever things I feel like. I then Recall (spell, scroll, potion, item) back to exactly where I was. Even deep in a dungeon, unlike in Oblivion, Fallout 3, or Skyrim.
Yes, it took a little more setup in Morrowind (since you first had to get a source of those spell effects). But once you had done that setup, you could bounce all over the freakin' place.
The deployment of "dumbing down" and the generic (stupid) "casual" insults, reveals your true point of view - not actually trying to suggest improvements, but just railing against whatever bits of modern gaming that you happen to dislike. Having seen you use those words, there's no longer a reason to discuss the topic - there's nothing actually here to discuss, just empty words.