Examples I can think of is Rabbit MQ and Cassandra. But in general, we have some really battle-tested software these days that has become simpler to configure and run over time. People seem scared to run their own these days.
I happen to disagree strongly, though: lots of engineers in my experience undervalue the work of systems administrators and underestimate the effort needed to operationalize any technology.
Running your own is absolutely fine if you are willing to keep your stack small and invest time learning the tools you pick. But there are still horror stories of people thinking snapshots are backups, turning the wrong knobs and turning off fsync on their databases, ...
Most small startups are actually the ones who don’t really need SaaS services.
This has not been the case at multiple employers and or consulting clients.
If you're providing software to an enterprise this almost will never fly. That single docker container will have an outage when basically anything happens. The container dies, systemd fails to restart, node dies, network switch dies, data center has basically any major issue, etc.
I think your comment brings value just probably biased with your own experience of running a consumer to consumer startup.
A lot of SaaS promise infinite scalability—a need which often never comes to most small time startups.
But developers are part of this problem too. There's plenty of times where I see devs immediately reach for tools instead of learning just a little bit more about what they already have. My favorite example is when folks want to add a NoSQL db into the mix on top of a traditional db. Not because there's a real performance need, but because for their use case it is 'easier'. Never mind that their problem possibly could have been solved by just writing their own SQL instead of trusting a garbage ORM...