I’ve noticed a similar trend in Australasia with Temminck’s golden cat one of many species phased out in the past 15 years. They weren’t suitable to captivity. Breeding was only achieved at two of the five zoos that tried to breed them and this was only when the breeding pairs were kept off display.
Even with relatively small exhibits, it was amazing how adept at hiding they were and being a species the visitors never got to see meant they weren’t considered enabling by zoo management.
Personally, they’re one of my favourite species and one I greatly miss seeing, but I can understand the reasons for their phasing out.
Curiously one of our last golden cats (Saigon) will also be one of Europe’s last golden cats. He was born at Auckland Zoo in 2005.