I like a lot of the answers, but something else I'd add: lots of "popular" architectures from the late 00s and early 2010s have fallen by the wayside because people realized "You're not Google. Your company will never be Google."
That is, there was a big desire around that time period to "build it how the big successful companies built it." But since then, a lot of us have realized that complexity isn't necessary for 99% of companies. When you couple that with hardware and standard databases getting much better, there are just fewer and fewer companies who need all of these "scalability tricks".
My bar for "Is there a reason we can't just do this all in Postgres?" is much, much higher than it was a decade ago.
That is, there was a big desire around that time period to "build it how the big successful companies built it." But since then, a lot of us have realized that complexity isn't necessary for 99% of companies. When you couple that with hardware and standard databases getting much better, there are just fewer and fewer companies who need all of these "scalability tricks".
My bar for "Is there a reason we can't just do this all in Postgres?" is much, much higher than it was a decade ago.