Not saying they don't exist, just that it's extremely rare to see. I live within sight of a popular path/course and can say that I've only seen it a handful of times- generally most appear to be commuters or part-time (overweight or with kids) riders. You never see it within a group, which leads me to point at the "me too" mentality.
It is very popular to see plain designs in stores. Cycle clothing found at REI (only as that was where i was most recently) is 90% non logoed (with exception of small brand logos) Most brands of cycle clothing come without printed designs or more than tiny logos.
Club rides have many riders with solid/solid print designs, the other half with logos/design from moderate to over the top. I see local cycling team training in fully logoed and color patterned gear, all matching each other.
Al