“If a top college, no matter how selective, does not offer early option it can find itself locked out of top applicants pool.”
That will never happen unless HYPSM and Cal Tech switch to ED. As long as those colleges are offering EA or SCEA, the top colleges, at least those six, will not get locked out. Given Stanford’s yield is 88% I think, you have to assume that 88% of the applicants to Stanford are not applying ED anywhere, and those are best of the best. Similar with STEM, if you’re applying to MIT, you’re not applying ED anywhere. The better applicant you are, the less you need ED.