uh, maybe you only have the issue that you need redundancies because you have so many pieces of software that can barf?

I mean it will happen regardless just from the side effects of complexity. With a simpler system you can at least save on maintenance and overhead.

Yes, but if your web server goes down for whatever reason, you’d rather have some more for your load balancer to round robin. Things like physical host dying are not exactly unheard of. Same with DB, once you take money, you want that replication and quick failover and offsite backup.