Doing stuff on-prem or in a data centre _is_ hard though.
It's easy to look at a one-off deployment of a single server and remark on how much cheaper it is than RDS, and that's fine if that's all you need. But it completely skips past the reality of a real life resilient database server deployment: handling upgrades, disk failures, backups, hot standbys, encryption key management, keeping deployment scripts up to date, hardware support contracts and vendor management, the disaster recovery testing for the multi-site SAN fabric with fibre channel switches and redundant dedicated fibre, etc. Before the cloud, we actually had a staff member who was entirely dedicated to managing the database servers.
Plus as a bonus, not ever having to get up at 2AM and drive down to a data centre because there was a power failure due to a generator not kicking in, and it turns out the data centre hadn't adequately planned for the amount of remote hands techs they'd need in that scenario...
RDS is expensive on paper, but to get the same level of guarantees either yourself or through another provider always seems to end up costing about the same as RDS.
I have done all of this also, today I outsource the DB server and do everything else myself, including a local read replica and pg_dump backups as a hail mary.
Essentially all that pain of yonder years was essentially storage it was a F**ing nightmare running HA network storage before the days of SSDs. It was slower than RAID, 5X more expensive than RAID and generally involved an extreme amount of pain and/or expense (usually both). But these days you only actually need SANs or as we call it today block storage when you have data you care about, again you only have to care about backups when you have data you care about.
For absolutely all of us the side effect of moving away from monolithic 'pets' is that we have made the app layer not require any long term state itself. So today all you need is N X any random thing that might lose data or fail at any moment as your app servers and an external DB service (neon, planetscale, RDS), plus perhaps S3 for objects.
Database is one of those places where it's justified, I think. Application containers do not need the same level of care hence are easy to run yourself.
It's easy to look at a one-off deployment of a single server and remark on how much cheaper it is than RDS, and that's fine if that's all you need. But it completely skips past the reality of a real life resilient database server deployment: handling upgrades, disk failures, backups, hot standbys, encryption key management, keeping deployment scripts up to date, hardware support contracts and vendor management, the disaster recovery testing for the multi-site SAN fabric with fibre channel switches and redundant dedicated fibre, etc. Before the cloud, we actually had a staff member who was entirely dedicated to managing the database servers.
Plus as a bonus, not ever having to get up at 2AM and drive down to a data centre because there was a power failure due to a generator not kicking in, and it turns out the data centre hadn't adequately planned for the amount of remote hands techs they'd need in that scenario...
RDS is expensive on paper, but to get the same level of guarantees either yourself or through another provider always seems to end up costing about the same as RDS.