The DNS ecosystem is much more diverse. djbdns is considered to be the most secure, and there are a few other quality implementations. The root servers, for example, run a mixture of BIND and NSD, so no single bug can affect all of them.

bind has had ok funding over the years.

Though, bind 10 hasn't gone as well as planned - that's been other issues than funding though - https://ripe68.ripe.net/presentations/208-The_Decline_and_Fa...