I wonder if it's also that now their investors are going to expect growth on top of whatever accelerated growth they have experienced in this WFH era. meta wants a nice, predictable cruise uphill, not a sprint that they'll now need to continue, progress be damned.
Side note: that's a theory I've had regarding technological advancements in devices like phones. Apple, Samsung etc. want small incremental advancements they can drip-feed to consumers for stable growth, so they probably try to keep the big leaps infrequent. Yeah I know Moore's Law can't go on forever, and it might be getting to that point soon... alright I'll take off the tinfoil hat.