The company i worked for would have had systems quit working correctly. Dates would have been interpreted incorrectly and auto purchases would have stopped. They system I supported was fine due to actual date fields being used not string dates.
Many of the older systems were patched with what amounts to hacks extending the year issue 50 to 80 years depending on the hack date used. A simple if statement that handles the string dates based on the value of he year.
I can’t say what other systems at other companies would have done if they used these type “dates”. Much like global warming there was too much world ending reporting. I doubt things like electric grid care about dates.
Shucks, I can navigate with a map and compass and make engineering drawings with a t-square and triangles. I find it a bit scary that people of today couldn't run a business for a few days with just candles and pencils.
I also find it outrageous to discover that anyone could think sort errors would cause anything other than inconvenience. I have yet to find anyone who can cite a single case of that old Y2K problem being dangerous.