I've been at a couple of places where I've had similar experiences and I get to the point where I'll explain it once, and if they're not listening or discard the suggestion without really considering it, then I'll just wait for them to figure it out themselves.
I get paid either way.
I'm generally looking for another job when it gets to this point. It's not healthy to stick around when things get to that point.
I’ve been there. After a while, I realized that they’re paying for my advice. If they take it, awesome. If they don’t, and I feel like I did a good enough job communicating my reasons, then that’s their option, and their consequences.
I get it. The situational context makes a huge difference, too. Most of the people I advise now are Chief Something or Another. Their jobs are generally to take a whole lot of inputs and make business decisions. Maybe I’ll say “I don’t think we should do that because X”, and they’ll decide to do it anyway because Y is a higher priority. As long as it’s not something truly horrible, like “let’s sell our user list” or “we don’t have time to hash passwords” or something else egregious, eh, fine. They asked for my advice, I gave it, and they’re free to do whatever they want with it.
But sure, even then it’d get super annoying if they always ignored it. At some point it’d be obvious that my business goals don’t align well at all with theirs, so maybe it’s time to find a better fit.
I get paid either way.
I'm generally looking for another job when it gets to this point. It's not healthy to stick around when things get to that point.