Errr.... the guys who wrote code in the 1960s through to the 1980s didn't think their code would still be in use by the year 2000 so they used an abbreviated calendar year date format. Not sure if that really qualifies as a conspiracy.
Known problem, well understood, complexity was in the mitigation - finding instances of the code, correcting the date format and looking for regression issues in the legacy code. And believe me that cost millions upon millions of dollars to do. When people say "Y2K, there wasn't really a problem", I tell them - yes, there was a big problem - we had to spend a sh!tload of money fixing it before it happened.
Of course post-Brexit people don't like experts telling them what to do, or even telling them what actually happened, so you can take it or leave it.