It may well be that colorways are used and loved by many users and that's a success. You made something people like; well done!

That we are having this conversation at all I think could be considered evidence, though, that it was a strategic failure for Mozilla. How much public opinion is worth burning for how much increased usage of a new theme feature? In my opinion, very little.

That colorways work well, that the people who use them continue to do so, that they were technically well designed and well engineered, is one yardstick by which to measure success/failure. By that measure they are certainly a success. But another yardstick is "did they have a net-positive or net-negative effect on the organization", which is where I think it came up short.

Based on the things you've said it sounds like you and I are more or less on the same page.