As the most popular ones start having acceptance rates that are so low that most qualified applicants will be rejected, many applicants will start adding colleges which are slightly less popular. These colleges will become more popular, and more colleges will be added.
This is especially true for LACs, probably because, until recently, most people would never have heard of any LAC that was more than two states over. Almost nobody in Chicago would know of most NESCACs, and the name “Carleton” would have meant nothing to college-bound students in Boston.
As LACs become more popular, and as the number of students applying to all “elite” colleges increases, the number of popular LACs will increase.
What is interesting is that the least popular LACs are struggling to survive, and are closing. It seems that it is a race for some colleges as to whether they will be “discovered” before they are forced to close.
I would guess though, that colleges which are really struggling may have a difficult time attracting students.
Not to all LACs, but the ones that were somewhat less popular than colleges like CMC, Pomona, or Williams, meaning that they had acceptance rates in the 40%-50% range. Denison, Grinnell, Colgate, Kenyon, Scripps, Lafayette, Occidental, Denison, Connecticut, and some others have had dropping acceptance rates since 2010 or so.
Some solidly performing LACs are still not seeing rising applications, like Beloit, Lawrence University, Kalamazoo, etc.