No. They need to scale out because providers like AWS have outages. And so startups et al need to deploy in multiple AZ/regions in order to have as close to 100% uptime as possible. You can't do that with a well considered multi master style replication strategy which PostgreSQL frankly doesn't have.
>People that keep recommending PostgreSQL are rightfully ignoring this industry.
Sure. And soon enough they will be relegated to the dustbins of history. The trends don't lie.