I thought the B2 itself was just a re-release of the Losi XX. No?
Seriously, though, I got out of the hobby while the XX was still the king. When I came back many years later with hazy memories, I honestly thought the B2 looked like a complete ripoff of the XX. That was through the eyes of a casual observer. I am sure you folks in the know can point to at least 47 million differences, but to me, at a glance, ripoff.
To answer the question, though, I think Thunder Tiger complicates things a bit. Associated is really a company within a company. Their racing designs are sort of "dumbed down" or cheapened and released as different products at lower price points. I think that is very different than a Tamiya, Kyosho, or Schumacher. Those companies are largely intact as they were bitd. They are reliving their glory days just as much as we are.
I think Losi has a similar situation to Associated, and this may be why they seem to dance around the re-re game, releasing small Chinese replicas of their old stuff versus doing an actual re-release.