Good question. Probably, but it is not sure. Some home cats are also shy. For example, our older boy. He is quite like as you do describe it. Very nice homecat, but verry shy and watchful to guests. True, he is a russian blue, and many russians are known to be more or less shy. But all his children and grandchildren are more social than he...
I myself do like him this way. This way, I know I have his friendship because he wants to give it to me. Because he does like me. Not because I just happen to be here, and it it thursday...
So there surely are several factors, in practice making it very individual for each cat.
Even two siblings can differ. One semiferal kitten in a litter gets homecat in literally 5 minutes, for his sibling it takes perhaps several months... There are examples on this.
A rescued semiferal high preg (or with small kittens) semiferal / feral mom, being in a knowleable fostering home, makes it well.
These kittens usually get fostered into nice homecats. If handled much, they are allowed to meet different persons, perhaps also another cat, perhaps a freindly dog, etc...
For the mom it usually takes much longer time, but her children will be homecats... The moms usually do accept this!
Although other rescuers do describe it is almost impossible to socialize kittens properly being together with a shy, semiferal mom... These are usually amateurs, say a stable owner who tries to help a feral momma, or rather, her kittens.
I dont really know if they hadnt tried properly, or if this is one of those individual cases....
But most rescuers witness it goes just fine!
Good luck!
