Can de-centered lens be fixed? Experiences?

Yes, normally not much of a problem providing the lens hasn't suffered any physical damage.

I bought a used Canon 10-22 which had this problem, simply a case of removing the front cover ring and adjusting the front element housing back into the correct position.

BUT, it can be a very time consuming operation getting into exactly the right place when doing it by eye, the adjustment isn't a problem because there is a provision for adjustment built into the housing but getting it to the right place takes time. Obviously Canon have special equipment that enables them to align it quickly, I wouldn't imagine most camera repair places have the right gear.

I have since done a couple of other Canon lenses with equal success and found all these to have a similar adjustment on the front element.