I don't believe that to be true. Even if by usable you mean primarily can be used in production, I would still argue it's more usable that it was, even if I wouldn't label it strictly "usable." I wouldn't shell out to bc for math ops, for any number of reasons (including it being slower for my purposes), but I wouldn't call the bc utility unusable.

I don't trust its developers to deliver usable software reliably

I can't fault you for that conclusion, given your experiences. That said, developers involved in a project change over time, as does the influence of existing developers (and maybe you believe people can change, too). That conclusion may become more or less true over time, and indeed may have already changed. Perhaps some day you'll find a reason to be interested again, and find the experience more enjoyable. We can only hope. :)