> it was a good decade before they even admitted Perl 6 might take longer than expected

I was there at OSCon when Larry announced Perl6, and that it would be "out by Christmas". And I was there the next year, when he was asked about that, and cheekily replied "well, we never specified _which_ Christmas."

> well, we never specified _which_ Christmas.

The wider Perl community adopted that, and for years it was a running joke that Perl 6 would be "out by Christmas."

Of course, people outside the Perl community didn't get the joke. They just perceived it as the Perl community making promises about release dates and then missing them. That was some self-inflicted damage.