That argument doesn't make sense. UI has no impact on API compatibility. The only situation in which software would break is if it's doing screen scraping and a

That argument doesn't make sense. UI has no impact on API compatibility. The only situation in which software would break is if it's doing screen scraping and automated input, in which case that software deserves to break. Backwards compatibility is not an excuse to allow 20 years of tech debt to accumulate anyway.