That's true, the precedent is there, so that wasn't to say that it can't happen. I just meant more to put the emphasis on the "doesn't really do much" though. Cute's next two singles after that were still only comparable to their other 2008-2009 single sales figures and then their individual singles started to tank along with the rest of the groups. They didn't hit their resurgence until a few years later in early 2012 when they basically doubled their previous average. So while we have an instance of color shuffles happening after members leave, we don't really have a precedent for that alone being a catalyst for more popularity or higher sales.
From the perspective of old men in business suits, without a comparable success, they're just as likely to see it as potentially alienating the fans that would feel obligated to buy the new merchandise if they don't have something else to make it feel justified like a name change, new members, or something else to shake things up. The safe options that they're likely to instead take are to just feel out the sales with another single or two and do nothing, or debut some more KSS. Since they've already announced a new single, it seems they went with the former, but whether or not they change tactics after that will just depend on the sales.