It is. But as you've seen over the years, it causes an unworkable amount of upset and alarm when large numbers of failures appear on the trunk all at once, and people who would otherwise be dealing with release issues now have trunk issues to worry about.
That's why I always advocated independent library development.
We all (well, many of us) want that. We're not there yet.
Unless I'm missing something, that model doesn't entirely solve these problems, we'd have a situation where: * Everyone tests independently against the last release, and everything on it's own looks great. * A change that removes features gets merged to release and.... oops now the release branch is broken. So we'd need some kind of integration testing as well.... Cheers, John.