Really depends. Building a system from components can be quite tricky, as the components tend to only play nicely together if they've been built for one anothe

Really depends. Building a system from components can be quite tricky, as the components tend to only play nicely together if they've been built for one another, or to some agreed upon spec. Otherwise you have to be very fluent in all of them, and write glue code. And there be dragons. APIs tend to be all over the place, yes, but you can have a well defined API spec that really can allow specific implementations to be swapped out fairly trivially, such that it really is more like 'components'. Think SQL, for instance. I think you may just be noticing that when things adhere to a spec, they tend to be able to combined pretty easily; if not, they don't.