Well, I reply to this with YES and NO..
YES
because this skill decay is a little odd.. of course you wouldn't forget how to do things even in real life.. you might just get rusty..
On my opinion, there should be a different system for skills and the luck and quality for making it.
For example.. you have 60 basketry and can make a Gold Basket... after a while your basketry level gone down to 30.. now what will happen is that you won't forget how to make the Gold Basket, but instead, your chance of making it and the quality will go down.
NO
because this system has a point.. skills really go down, but not as far and fast as this.. it could take years to forget something. I would happy to have this system with a few fixes and things. and also, after you forgot something you have learned, after a few review, you should and would learn it a little faster than learning it first time.
REFERENCE:
My own Experience;
I didn't forget how to use a fishing rod even after not fishing for 2 years (in real life),
I never forget how to drive a car even after a few months,
I never forget how to cook (maybe the taste changes),
and that's that..