It's a C Suite decision and they made the wrong call for short term shareholder value (greed). IT was simply seen as just another cost, and "cost cutting is in our DNA" BA just wasn't going to invest. Having seen many businesses leap from ancient data centres to cloud managed services, I knew BA were dinosaurs and it's long past time this stuff breaks. My current employer is the same, our current migration is 10 times more painful as it's decades late.