>>55966762I think for many people that the time period of Generation V was a nadir in the overall fanbase's interest in Pokemon.
It's hard to say exactly how much damage BW, Gates To Infinity, etc., were going to cause to the Pokemon franchise's popularity long-term, given how successful Generation VI with XY was in galvanizing interest. The only real way of gauging this is just counting how many people who weren't kids back then (i.e., were teenagers or older), who look back and still assess Gen V negatively.
Unovabortions like to imagine that most people now have done a double-take on it, when the reality is just that their cohort all grew up.But since there's never been a systematic survey of what people hated about it then, there's little definitive way of going about finding out why and how many people hate it even now.
People who hate BW will probably confidently tell you it would have killed the franchise. The sales numbers did dip and there's been no other modern games before the past half decade that received worse publicity.