Marriott has the most exclusive top elite tier with published earning criteria. The Ambassador level requires not just 100 nights in hotels but also a minimum of $23,000 in spend, nearly impossible to achieve in many parts of the world with low hotel rates.
Yet for three years the Ambassador level didn’t even come with Ambassador service. Marriott eliminated dedicated Ambassadors during the pandemic, even while Hyatt (which offers concierges at just 60 nights without minimum spend) kept theirs.