“We see a need to build X. Its fancy and shiny new technology. It is right thing to do. What problem does it solve? Dont worry about that. We are going to strong arm a few teams to adopt this, even though it costs money to build and support. Sure, we can make investment in Y instead but dont want to because solving Y doesn’t let us increase head count or write promotion documents. Plus, X is very complex. It guarantees job security for people who understand it. Let’s not worry about what happens if these people then quit and make this thing everyone elses problem”
Its not always outright nefarious reasons but there’s always an incentive structure incentivizing wrong behavior because it benefits individuals or is cool or fun thing to work on, without having meaningful impact or business value