I think (wait to be proved wrong!) that I am in a small minority. I am Lifetime Platinum and have NEVER stayed on business. I joined Marriott Rewards in 2003.I was Gold for 2006 and 2007 and I have made Platinum in 2008, 2009, 2010, 2011, 2012 and 2013 without the rollover nights to assist (I did get some, but got 75 actual nights anyway). I made Lifetime by the beginning of 2014 and in 2014 still had 70 nights. Although I would only be Lifetime Gold under the old qualification, I still have the pre-requisites of the old system: over 2m points, 12 years membership and at least one year at Platinum. Will probably make 1000 nights by 2017.
I do like to emphasise that I have made this not on business, I think it does deliver me a few extras, though some hotels (Maidstone, are you listening) couldn't give two hoots!