Apart from the wider footprint, why does requiring 55 nights per year with Hyatt now mean that you should rush over to do 50/75 nights with Marriott?

If you want top status based on stays, then you should move to SPG for as long as that lasts and indirectly get Marriott status that way.

If you were Hyatt Diamond with 25 stays but 30-something nights, then you might not have been getting much benefit anyhow so you should have been concentrating on a wide footprint chain in the first place... (except we all know that top-end Hyatts are much better as a Diamond than virtually all Marriotts as a Platinum...)