Few things...echoing the comments already made by some about the many factors that contribute to a person's choice to choose one program over another, with regards to Yale, and modern/contemporary specifically, the strength of that program dipped exponentially after the exodus of Nemerov, Joselit, and Jones around 2012 and is honestly only back on the up and up since Pam Lee started in the fall. Over the last five years CUNY was objectively the better program for the contemporary track. I also can state for a fact that 3 williams grads in 19th century from the last 3 years turned down Tim Barringer for Bridget Alsdorf at Princeton (x2) and André Dombrowski at Penn. Given the tilt in the field towards the study of art of the last 200 years, it tracks that if Williams too is primarily producing modern/contemporary PhD hopefuls they wouldn't place at Yale (except in the case of the sole first year at Yale from Williams who pivoted to medieval studies--so you wouldn't have caught them--and incidentally the Pitt person is also a medievalist). Between Princeton and Harvard there's definitely 10 williams grads in years 1-3 and more who are ABD; two in each class at Princeton and 3 in Harvard's second year class alone lol.
I've actually begun to suspect that if there's any problem with Williams' placement it's that they're producing too many hyper-qualified candidates. Where no more than 5 -7 years ago you could reasonably graduate with an MA and get a half decent museum job, the trend towards professionalization in museums has made competition for PhDs even starker. Of course programs want to bring in classes with diverse intellectual backgrounds, so when 4+ williams grads with the same LORs and similar CVs apply to work with the same advisor maybe they can only justify taking one (this may or may not have happened w Rachael DeLue at Princeton in last year's cycle).
The above is pedantry in any case: bottom line no one should pay for an MA in art history, and the Courtauld doesn't fully fund. You can tell yourself what you want about placement trends at Williams, but it doesn't graduate students into the extremely bleak job market/PhD circuit saddled with 10,000s in debt.