Moving to the ACC was by no means wrong. The problem is simply that most of the ACC schools, and particularly those in the Northeast, are supported by alumni and fans that tend to care about things other than college football.
The trends have been plain to see since nearly the time we joined. The ACC had to go out and get Notre Dame to commit and Texas in order to be viable. When the SEC moved its footprint into Texas, that was the beginning of the end for the ACC. The GOR stays the execution, but its coming (assuming college football even exists by then).