Marriott has completely disappeared for us as well. Last year, they were our #1 chain, as we had (and still have) a corporate rate with them across the U.S., one that works at *most* Marriotts. But it's now a 1-day cancel, and that makes it an out-of-policy booking. We're a midsized company with a moderate amount of travel...I fully realize that Marriott does not care about our plight one bit.
Oddly enough, we still have a random mix of Hiltons and Starwoods, plus quite a few Hyatts. Our HH and SPG negotiated rates were always kind of random, so I suspect we had the 6PM cancel negotiated at the property level. (So we have maybe 1 out of every 4 or 5 urban Hiltons, for example.)
I'm probably going to end up a mid-tier with Hyatt this year, simply because I can't be bothered to continually ask for out-of-policy Marriotts. However, I do start most of my business trips with an early-morning flight, so as soon as I land in the destination city, I guess I can always do a quick Marriott check to see if our rate is still available... Either that, or I'll just find a couple Hyatts that I like...
Frustrating that we're being forced to jump through hoops that didn't exist before.