Looking at the various projections for the field of 68 (that still sounds weird) it looks the ACC will have a minimum of four teams and possibly up to six depending on how Boston College and Maryland finish.
That number would be right in line with how the conference has done over the last ten years.
ACC NCAA TOURNAMENT BIDS BY YEAR
The problem is that the ACC has only one national title contender (Duke) and the Blue Devils are also the only team likely to even make the Sweet 16 or beyond.
The top of your conference is always judged more so than the bottom and that is why the ACC is getting hammered this year (though the bottom ain't great either).
Interesting to note the conference has done about the same in bids before and and after expansion midway through the decade.
But what the ACC has lacked in quantity has been made up in quality with five of the last 10 national champions.