Responsible for? No, no no no. No. No.
Unintentionally contribute to? Yes.
Really, the only think responsible for the boom in furry fandom is the Internet. There have probably always been furries out there, but you might have one or two people who feel that way and were too scared to come out and tell others about it since, you know, anyone who isn't a furry tends to both laugh at them and/or call them sick perverts. Toss in 1 part anonymity, and 1 part "I can talk to people anywhere in the world", and suddenly that scared furry in Ontario, California is talking to someone in Oil Springs, Ontario about how they sort of sometimes feel like they're part animal, and like wearing something that reminds them of their favourite animal, and the person in Oil Springs says "I like to do that too!" and BAM!
Yiffing.
No internet, less yiffing.
Unintentionally contribute to? Yes.
Really, the only think responsible for the boom in furry fandom is the Internet. There have probably always been furries out there, but you might have one or two people who feel that way and were too scared to come out and tell others about it since, you know, anyone who isn't a furry tends to both laugh at them and/or call them sick perverts. Toss in 1 part anonymity, and 1 part "I can talk to people anywhere in the world", and suddenly that scared furry in Ontario, California is talking to someone in Oil Springs, Ontario about how they sort of sometimes feel like they're part animal, and like wearing something that reminds them of their favourite animal, and the person in Oil Springs says "I like to do that too!" and BAM!
Yiffing.
No internet, less yiffing.