When I was a crew chief, my 7-level CDCs covered A-10/F-15/F-16/U-2/MQ-9/Global Hawks, with the idea was that we'd universally assignable. I've stayed in contact with a few AD guys from my crew chief training days. One worked F-16s for a few assignments, now is now an NCO in A-10s, another was recently assigned to KC-135s. Every platform has quirks/intricacies that are relevant even when you're leadership, and retaining long term knowledge on the platform is huge. There is a reason we have such awesome mx in the ANG.