Why are BSAs so cheap?

First time I ever rode a bike, it was an ancient BSA Victor (in Ship of Theseus condition...) on my grandfather's farm. It wasn't exactly a great bike but I was delighted as a teenager to be riding across a field...

I'm now in the market for a new (or used...) motorcycle and BSA popped into my head. I just had a look at their website, and even a new the Gold Star 650 starts at 6k - while a Bonneville starts at twice that. You can find them nearly new for as low as 4-5k on Autotrader... Scrambler model is even cheaper, and their wee Bantam is 3.5k new.

Is it just because of the off-the-shelf Rotax engine, or Indian assembly, or do people see the modern revival as a "money-making ploy"... I'd be keen to hear from the community.