If your boss's boss or peers signed a contract for $1m a year from Oracle, you're going to use Oracle even if Postgres is a better product. And the only way to use Postgres in this situation is if they don't know you're running it. Which puts you in the uncomfortable situation of wanting to say, "But Oracle sucks, look how successful we've been at using Postgres?".

Basically if you don't already know that someone higher up the food chain is comfortable with saying, "I've made a huge mistake", you aren't going to 'help' them learn to do it by pointing out they fucked up. What they're going to hear is that you're asking them to say, "I just wasted a million dollars of company money on something everybody hates," which not only are they not going to do, but they're going to start thinking about how to shoot the messenger.

As many conversations go in a couple of my hobbies and talking to friends and acquaintances about health concerns, the answer often starts with, "first, get a time machine" and ends with, "or learn to live with it," often with some useful compromises in between.

One of the important things to do early in your tenure at a place is to bid various people in the management chain and those who seem to be on a management track to see how open they are to having their minds changed. Because you want to know this when the stakes are low (also the blowback on low stakes things seems to be less problematic). Then you know if or when a boondoggle is in the making whether you can stop it before it starts, or amplify all of the problems and kill it along the way, or whether you should keep your head down and conspire to keep the 'doggle at arm's length with those who agree with you.