My guess is that it was a feature that was used rarely and only by a tiny proportion of the userbase. That kind of feature is always at a high risk of being cut

My guess is that it was a feature that was used rarely and only by a tiny proportion of the userbase. That kind of feature is always at a high risk of being cut if it causes even the tiniest problem. In this specific case, if an option that's used 0.01% of the time is making the UI look cramped when the contents of a dropdown get inlined, why not remove it? Nobody's going to care. Except that sometimes people do care. It's pretty hard to know in advance whether https://xkcd.com/1172/ https://xkcd.com/1172/ will apply or not. You can't run any kind of UX study because odds are that the only way you get people to interact with the feature is by making up an artificial scenario that basically forces them to use it. You can't even run an A/B test because every fewer people will actually reduce their YouTube usage over this. They might be unhappy, but their level of happiness doesn't show up in metrics.