Not sure.
I'm curious do you work in OOH advertising? Most people wouldn't use or know the term "wallscape".
No I am a political science and economics major (almost done) at OSU and I am applying to grad schools for Public Policy and Urban Analysis.
I don't post here often but I wouldn't underestimate the number of individuals that study and have interests in urban areas. And if I did work for them wouldn't I already know the answer to my question? ;)
Back on the topic. I find it a little too much of a coincidence that nearly all of the large wall-scapes, downtown, are being replaced at once.
I think that some investigating could be done to find the answer. It may be that Orange Barrel is putting all ads on the same timeline and replacing them at once, but this would seem like an odd business decision.
Each ad has to pass the Downtown Commission. The commission would have to spend a lot of time, at one meeting, approving all of the new ads. They usually space out new ad postings (as firms demand ads at differing times and the commission does not like to be bogged down by many ad proposals at once.)