Chaos often begins as several minor exceptions nobody corrected.

Standards fail through permitted exceptions. One thing left out of place, one deadline allowed to slip, one rule waived because the circumstances were unusual, and each of those makes the next exception easier to justify. Nobody decided to abandon the standard. It eroded through reasonable individual cases.

Watch for the first exception rather than the tenth. Correcting it immediately is trivial and prevents the pattern from establishing. That is why small corrections early are worth more than large ones later.