The author brings up the point, but I have always found surprising how much more expensive managed databases are than a comparable VPS.
I would expect a little bit more as a cost of the convenience, but in my experience it's generally multiple times the expense. It's wild.
This has kept me away from managed databases in all but my largest projects.
Yes if the DB is 5x the VM and the the VM is 10x the dedicated server from say OVH etc. then you are payng 50x.
Once they convince you that you can’t do it yourself, you end up relying on them, but didn’t develop the skills you would need to migrate to another provider when they start raising prices. And they keep raising prices because by then you have no choice.