It's more the case that the panic around IP space exhaustion turned out to be unfounded - or at least we've been able to work around it for much much longer than expected. Back in 1994 the IETF predicted that the internet would stop working in 3-7 years. Almost 30 years later we're still going. So there's no sense of urgency to invent something better.

For the record I also believe that v6 will be abandoned and eventually replaced, most likely with a backwards-compatible protocol. Or something that provides a more compelling reason to upgrade than v6, which basically has nothing. Or at least nothing that people want - the lack of NAT is really an anti-feature.

The history of tech is littered with "standards" that never achieved critical mass.