I didn't notice any drop in quality after Stuart Spector retired, because they were already working with Korg for distribution before that. Spector basses still have the same quality they always have, just with new trendy features like fanned frets and whatnot.
What made Tobias basses great was the neck profile. They have an asymmetrical neck profile that is fatter on the low string side and thinner on the high side. It's super comfortable to play. First thing Gibson did is make the Toby Pro bass in Korea instead of Japan, and they used the Gibson neck profile on them for economy. They were still nice, but not as good as the real thing. Now, a Toby Pro is a joke. It's a junk ass bolt on with cheap components. It's so far removed from what they used to be.