When you scale horizontally from day one, it usually gives fault tolerance for online service, and this story is not very friendly in case of vertically scaled PG.
My point is that in PG, fault tolerance requires untrivial investments.
If you pick horizontally scalable DB (foundationdb, cocroachdb, scylladb, tidb, etc) they all give you fault tolerance for free without much involvement from your side, because it is part of the nature of those DBs.
Everyone is hung up making their shit "scalable" like its a systems design interview at google in 2010.
Now a days you get a box with 600+ cores and 4TB of RAM. That is going to cover a very very large percentage of most enterprises.