Do you think a lot of that is scaling pain... like what if they're making cuts to the more expensive reasoning layers to gain more scale. Seems more plausible to me that the teams keeping the lights on have been doing optimization work to save cost and improve speed. The result during those optimizations might not be immediately obvious to the team and then they push deploy and only through anecdotal evidence such as yours can they determine the result of their clever optimization resulted in a deteriorated user experience... I mean think about doing a UI update that improves site performance but has the side effect of making the site appear to load slower because the transition effects are removed... Just my 2 cents trying to think more like their are humans supporting that thing that grew at a crazy speed to 100 million users.