I have no clue why this is an issue.
If the plane doesn’t have a safety vest and it’s required for destination, fill out an ASAP or safety report. A few of those and there will be safety vests popping up in planes (assuming the safety department/committee is good and the FAA rep who oversees ASAPs isn’t asleep)
If it isn’t required, either don’t wear one or bring your own for added safety.
Really that simple.