And those conventions change over time. So you might write something using Java EJBs at some point and then the world moves on and engineers no longer know how those things work. What looked like a great architecture is now confusing for most engineers.
That's true, and weird unorthodox architectures can actually end up being more stable in the long run, especially if their design was an intrinsic fit for the domain. A weird architecture that is a good fit for its domain often has simple ways of meeting key requirements that would have been more costly to develop with more conventional techniques. I'm just hallucinating this from your comment upthread, but a requirement like "making sure audit logs are kept" is the sort of thing I mean. Any architecture can do that, but some make it much easier. When a business starts out with a weird architecture in its early days and ends up succeeding, it's possible that that weirdness gave some competitive advantage.
