I've just that it's possible to level all skills to 100.

If this is the case, then why is it important to only focus on a certain few?

it isn't almost everyone becomes a jack of all trades

For example, if your Archery skill is 61 and you raise it to 62, that will push you more towards overall leveling up then say raising your Conjuration skill from 23 to 24.

Because the more skill levels you gain the slower they are acquired. If you stick with a few skills they will level faster.

You could level all skills to 100 in MW/OB, but it took a long time and you usually make new characters to focus on other play styles anyways.

So nothing new.

The perk system requires you to select which skills you will improve upon in that respect. You can be a jack of all trades but only so many benefits that take the skill set to the next level.
Also, it takes a really long time to build everything up.

"Jack of all trades" implies "master of none".

In short? The perk system. You only can select about 70 perks out of 280. 220 of those are unique perks. 60 are ranks. So you only can get about 25% of the perks in any playthrough.

yeah perk system. oh and who dint make atleast one character in oblivion, morrowind and fallout 3 with 100 everything?
anyways TO ME, elders scrolls is a game where you replay over and over and over and over again with different characters. play each one for like 45 hours then make a new one. got me to 1000 hours in oblivion =0, not sure about morrowind or fallout 3 but ive played more then 500 hours in each atleast
for me once ive master the archetype and done the quests i wont to do, i just start another character.

With the perks system, a fully "perked" skill is like four times more effective than an empty one, this keeps the characters different

You can only put the really good perks on your high level skills, and you can't get all the perks, so specializing will be important, especially at low - medium level.

Why would you master all of them? Is their a real point to having 100 in one handed and two handed, for example? What would a Paladin do with pickpocket skill? What use is block to a pure mage?

Because they nerfed the hell out of us with the "Perk" system, killing our ability to eventually master everything - something many people praise but which I feel is an attack on the essence of TES.

I liked my MOAT, but I'll try this nerfed system for exactly one playthrough before modding the [censored] out of it. (And compensating by strengthening monsters. I'm not looking for an easy game, but for the potential to master everything given enough effort and time).