I remember doing the math on being a 'Florida cruiser' and how if I lived in south Florida I could make Diamond Plus (no Pinnacle at the time), with just twelve three - night cruises in a junior suite. The rules at that time being 1 point per cruise (regardless of whether it was 3 days or 12 days), and 2 points if in a suite or if it was 13 days or longer.
If you had the time and money you could go from new cruiser to the highest member level in 36 days. If I lived within an hour driving time of a cruise port I'd be doing at least monthly cruises too.
And let's be honest - that is how "Super Mario" made his lofty record.