It's not just the technical costs of recomposing to achieve a jaoin; it's also diversity of this kind makes long-term maintenance a nightmare, and moving people/functionality/whatever between apps almost impossible.
If everybody cowboys their own storage, you're risking building up a legacy cruft that's very hard to work your way out of later.
The costs if recomposing later can be prohibitive, if a few particularly poor choices were made early on, and the hidden costs of inflexibility can bite too.
There's nothing wrong with outsourcing storage; that's not the issue - the issue is the culture in which it's easier to just not talk to the rest of the company (assuming the company is small enough to have any kind of cohesion in the firs place). If it's too expensive to talk (or even pick from a few common defaults) beforehand, how are you ever going to interop later on? You're getting the downsides of a large organization without the upsides.
If everybody cowboys their own storage, you're risking building up a legacy cruft that's very hard to work your way out of later.
The costs if recomposing later can be prohibitive, if a few particularly poor choices were made early on, and the hidden costs of inflexibility can bite too.
There's nothing wrong with outsourcing storage; that's not the issue - the issue is the culture in which it's easier to just not talk to the rest of the company (assuming the company is small enough to have any kind of cohesion in the firs place). If it's too expensive to talk (or even pick from a few common defaults) beforehand, how are you ever going to interop later on? You're getting the downsides of a large organization without the upsides.