If you can afford all your components sharing the same database without creating a big dependency hell, then your problem is _too small_ for microservices.
If your problem is so large that you have to split it up to manage its complexity, start considering microservices (it might still not be the right option for you).
Yes, they do fine as examples. I have worked both on decades old booking systems and banking software. Both were dependency hells. Refactoring was impossible. Everybody was super-careful even with tiny changes because the risk to break something was just too high.
If it could be avoided, these systems were not touched anymore. Instead, other applications where attached to the front and sides.
I don't think so. For example, the Linux kernel is old, but still quite well maintainable.
So I would say: it applies to systems where proper modularization was neglected. In the anecdotical cases I referred to, one major element of this deficiency was a complex database, shared across the whole system.
