My fear is companies without in-house RDBMS expertise see these products as a way to continue to avoid getting that expertise.
a distributed database is potentially more complicated to operate, and optimize, and because its new and potentially has more sharp edges maybe less reliable (?) but the extraction of moderate sized datasets doesn't really seem to be an obvious failing.
People who bang on about Postgres replication have rarely setup replication in Postgres themselves and that too in the 100a of Pb scale.
MySQL replication works well and can be scaled more easily (relative to Postgres) but has its own problems. eg., DDL is still a nightmare, lag is a real problem, usually masked by async replication. But then eventual consistency makes the application developers life more complicated.