What makes you think it takes more skills or knowledge to restore a 150 than it does to build a kitplane?
I understand it doesn't take more skill, BUT the FAA doesn't seem to agree. If they did, everyone would be able to perform annuals or modifications on their 150/152's. Maybe I'm wrong, but if I'm responsible for my homebuilt in the eyes of the FAA, why can't I be responsible for my 150? Why do I need AP supervision on a " certified " aircraft and not with a homebuilt?
Clearly you can see I don't completely understand the FAA. I'm working on it, so go gentle.