In my day job I correct people from using the team legacy systems to the incumbent system many many times. I'll allow legacy if there's a new system implemented and transition in progress but unless that's happening, it's not legacy yet.
People who don't want to fund maintenance on something love calling it legacy and are then surprised when it breaks and 'the legacy system' was still so important!
I feel sorry for the person in the 50deg cold aisle in the datacenter wondering whats 'least important' in this mess that could be shut off to keep the most critical stuff going. Clearly they never reached a decision on that!