When a software startup fails it’s rare that we ever get to find out the real reason for it. The straw that broke the camels back gets the blame - the recession, some hackers, Google, whatever. Nobody goes to the newspaper saying hey, we neglected every possible aspect of care and maintenance over the years, put a bunch of interns on fixing issues using spreadsheets and raw SQL and bled our customers dry over a decade until they all left. Usually the bigco that got suckered into acquiring them gets the blame and the founders are on a yacht in the Caribbean.
Tech debt won’t kill a company but it will strip away its immune system leaving it vulnerable to the slightest hiccup. Then the deadly hiccup gets the blame.