Went through this exact scenario at my job recently. As the tech lead/architect of an org I reviewed a bunch of recently released projects and identified areas that needed critical improvements because they had major reliability/performance issues. One team had multiple releases at the top of the list, and their PM and eng manager (and really everyone else up the chain) simply ignored all concerns because they had to…
Well, you could dust off the old email and 'mistakenly' send it again. Though it will seem petty, a small fraction might rethink the past few months.
I build something that depends on many systems that others have created and that uses data from probably about every dataset we have. What I build also has very high customer visibility. So whenever something breaks upstream, the first place customers notice the problem is in the system I maintain. Psychologically, people begin to develop a mental association around your system being a “problem” if it keeps getting brought up as the starting point of SEV discussions and customer tickets.
As a result, a lot of what I do now is defensive. I investigate and reverse engineer upstream codebases to identify likely failure modes, and I spend hours analyzing datasets of questionable origin for data quality issues and inconsistencies. I document and date stamp all of the problems that I find, file bug reports and assign them to the relevant teams, and write proposals describing potential solutions to what I see as large architectural design flaws that will come back to haunt us at some point.
All of this work is promptly ignored with “not enough bandwidth right now” or “not a priority compared to feature development”. Which is fine. I document all of those responses too.
Then eventually, something breaks in a big way that is again first noticed by customers within the system I am responsible for. In the past, I would immediately drop what I was doing and scramble into investigation mode for a few days to prove I wasn’t the root cause of the X hundred thousand dollar issue, er... I mean the blameless SEV review & postmortem... but more recently my preemption seems to be paying off, and lately I just reply to the panic with a bunch of links to old Slack threads (where we already discussed the issue), the documents and proposals I created (that no one read), or the bug reports I filed (that were never followed up on).
Perhaps it does come across as a bit petty, but I try to be as polite as I can, and from my perspective it’s an improvement over the previous situation. The only downside is that all of this preventative work takes away time from the primary work that I was hired to do.