[fendy3002]

Indeed. So with monolith usually we already have 3-4 (or more) somewhat reliable systems, and one non-reliable system which is your monolithic app. Why add other non reliable systems if you don't really need it?

Making a system to be reliable is really really hard and take many resources, which seldom companies pursuit.

[spion]

just because all the code is in one place doesn't mean its one system.