Functional I can agree with. But if that's the real reason we'd see more unadorned jersey's (and if visibility is the factor they'd have some sort of reflective quality). From what I see, the logos and designs tend to camouflage imperfections.
There are many bike specific clothing available without any logos, many available without any printed design/picture and many available with just fabric design and always available with just a solid color.
Only one of the many jerseys I have has words on it and they are not in any way related to any businesses. The rest are all solid color or design created with varied fabric panel color differences.
The functions I want from a jersey: Cool in summer heat, does not flap around in wind, has rear pockets and a front zipper to control ventilation, long enough so it prevents bare skin from showing on my backside when on bike no matter what shorts/pants I am wearing and colors that provides visibility in less than ideal conditions, generally lighter colors such as white and yellow.
Al