As a sometimes chatterer, it's a mix of complaining about the annoying changes in v6 that weren't just lengthening the address fields, pointing out that the migration is taking forever, and implying a less disruptive design could have rolled out faster.
For a long time, there really was next to no progress. Between the introduction in 1996 and about 2011, there was very little adoption. And since 2012 when pushing really started, we're at about 50% globally, with large variance by country and network type. 15 years between creation and real deployment seems like a lot, and 15 years of deployment getting to 50% also seems likes a lot.
But wikipedia says touch tone dialing was first offered to consumers in the 1960s and didn't become majority until the 1980s, so maybe 30 years isn't that slow.