That’s interesting. But there’s a whole lot of difference between colleges that don’t offer any early option at all (Cal, UCLA), and colleges that offer unrestricted EA (MIT, Caltech,USC). There’s not so much difference between the latter group and the many, many colleges (but not so many in the top 30) that offer rolling admissions (which is what Michigan did until recently, even though it was clear it has a de facto EA program). I think it also makes a lot of difference to students whether a college releases its early determinations before (most of the above) or after (Virginia) the due date for applying to competitive institutions.
I am also not sure why people care so much about the restriction that some non-HYPS colleges put on their EA program: that you can’t have applied ED somewhere else simultaneously (but simultaneous EA applications are alright). It is interesting to note that, arguably, none of the colleges listed above who offer EA has strong ED competitors, except for Virginia and Michigan, and in Virginia’s case it would find out about ED acceptances well before it released its early actions. Chicago certainly has strong ED competitors. Over half the kids I know who have applied EA to Chicago had simultaneous ED applications elsewhere, including Columbia, Penn, Brown, and Northwestern.
Also, the list of top-30 colleges that DO offer unrestricted EA is even shorter than that – because it excludes the two UCs and still includes Chicago.