What it means is that this was not something that was a thoughtless little "oopsie", something that can be fixed with a simple flip of a switch to bring back the feature, or cut and paste a few lines of code. It means that some actual, deliberate thought (twisted or uninformed, perhaps, and done without consulting anyone with real familiarity how people actually use their product) went into the change. So, it was probably something done with repercussions throughout the code base, maybe because it made some things easier for the coder to deal with in the implementation of a larger code change, maybe for another reason. But it was a relatively involved thing. So, now that they're seeing they made a mistake (*if* they're seeing and understanding that), they need to not just undo what they did. If it really was part of another more involved change that this was just a side-effect of, they have to figure out how to bring back the desired feature AND keep whatever code structure they were putting in place. In other words, they have to do the much harder work of undoing their screw-up while keeping the other stuff that went along with it.
In short: Don't hold your breath. When the Mac OS removed the simple, one-click column sorting features of Mail in the Catalina release (another prime example of a thoughtless removal of functionality), it took another major OS release, Big Sur, to bring it back. And even then, it wasn't exactly as it had been before.
