Its not fast because your average person isn't going to go out and spend 2hrs straight and be able to make 20, there leves will run out by time they hit 10. (My friend just joined and without linking he hits 10 after 8 leves).

Also new players wont even know what levelinking is, or even be able to do it properly because not knowing anyone, or not being able to get enough. They also probably will end up doing something else @ 10 and waiting for leves to come back.

Also it keeps them hooked, they dont feel the stupid useless grind, keeps players playing which is good for SE. So in the long run if SE can get more people staying by having this system, your opinion means absolute nothing. No ones does, sadly, its all about keeping people playing. And as you all know (or think) theres a lot of new people starting.