Tab groups have become one of Firefox’s most loved ways to stay organized — over 18 million people have used the feature since it launched earlier this year. Since then, we’ve been listening closely to feedback from the Mozilla Connect community to make this long-awaited feature even more helpful.
Make it an optional plugin or extension.
That way, the people who actually want and use it still have access, and they’d have access to accurate stats on how many of those people there are.
(Probably not enough to justify spending money on it.)