Rolling resistance is one factor but at those speeds aero is far more important. Of course being a lardarse like me will help too. My fastest on a roadie with 25mm is a bit over 100km/h. Did a Sagan tuck but coulda gone faster with aerobars and shit, maybe 110. It's fun.
But tire width doesn't really matter for rolling resistance anymore. With the shift to wide tires, companies are coming up with compounds and tread patterns that negate the effect of width. There are some 2.1" tires with RR in the low teens that are lightweight and handle well. There's almost no point to running anything under 32 now, unless you're looking for marginal aero gainz by matching tire width to external rim width.