Three that bolted on test coverage requirements at some point did so after the same catalyst. An unharmonious developer joining the team and subjects old, stable code to his opinions. "JQuery is the devil!" The developer cries, as he slashes and burns all the script tags into dust.
From there, he installs <his opinion> into the toolchain and spends a tireless 5 hours getting things to sort of work. "That's so much better." he remarks to no one as he scissor claps the dust off his hands.
The next day, users wake to a world in tatters. -- they submit tickets, pleas to an angry god to return the serenity of the benign that existed a mere day ago.
Rarely at this stage is time simply rewound - though it would be easy to do, someone will remark once. The conquerer of the old tech campaigns hard for hearts and minds. He's baffled that he is not greeted as a liberator!
"Spaces are superior to tabs, the fact that the code broke after I ran a regex replace is mostly python's fault. Stack overflow said that people who prefer spaces earn more so it's basically a good business decision to move on from here."
For some reason it's easier to be righteously indignant about destruction than maintenance. The strength and intensity of the usurper tends to triumph. Besides, client side validation should be easy to fix -- and there it is. The rest of the pantheon has been cowed. Cowed by the illusion of a few softball one point tickets ahead of them.
Unfortunately, glass shelled ecosystems created amidst the layers of code sediment don't fair well against the tremors of sed. Each softball one point ticket begets two 3 pointers, and so it snowballs.
When the unharmonious one is summoned by the pantheon to help fight back the cascade, he almost always bravely calls for a complete rewrite. "This is due to the fragility of the legacy system." he always reasons.
This is about the time that the descent into madness is halted by a call for test coverage. "We've experienced a lot of regressions recently, we should probably start writing tests."
This is also about the time our regicide leaves for another company.