Well, there's a reason for the second half of my comment. GIF isn't bad because it's old, it's bad and old, and it's unreasonable to expect it to continue to be supported because that's a nasty combination.

If something sucks but is still the standard technique in recent years then it's reasonable to think it should be supported. Similarly, if something is old but great, it's reasonable to think it should be supported. But GIF is old and crappy and there's no reason to expect support for something old and crappy to continue indefinitely.

I'd also note that your other examples have received substantial revisions over the years that have improved them enormously. I'd happily say the same thing about not supporting 1987-era C or filesystems.