I don’t think there is much consensus on terms like the upper middle class as applied to US society, but as I understand the usual academic definition, it means something like highly-educated, highly-compensated salaried professionals with a lot of work autonomy (like you have projects, cases, patients, students, etc., but are not constantly being directed in the details of your work by someone else).
The only group typically “above” this class in terms of annual income are the true upper class, people with very high incomes supported by the returns on various forms of invested capital (financial assets, real property ownership, business ownership, and so on). Some of these people “work” in the sense of managing such assets and properties and businesses and such (and so some CEOs and such may be in this group as well), but they are not doctors, lawyers, engineers, accountants, professors, or so on.
With that definition, I think the upper middle class (in the sense of professional class) is usually estimated to make up roughly 15% or so of US households, with the true upper class being under 1%. So top 16% by household income is the range where you are going to see a lot of people in the upper middle class. However, defined like this it is not purely an income measure, so some upper middle class households may not be quite top 16% by income, and some households in the top 16% by income may get there without the definitional education and work characteristics.
All this is kinda beside the point, though, because I agree with the observation that not all of the US upper middle class, however you define it, has gone to like an Ivy+, nor is demanding that from their children. Because of course the math can’t work out–15% of US households cannot send their kids to way less than 15% of US college slots, even adjusting for the fact not every US kid goes to college.
So if that defines the short-list college ambitions of a typical “tiger” parent, the upper middle class parents can’t all be tiger parents.
And of course that is the lived experience of many of us in the upper middle class. I do think it is very much the norm that most kids will go to a “good” college, because we all understand that as the likely next step after HS, and before some sort of professional career (usually although not always with some sort of postgraduate degree too). But having been through all this ourselves, we usually understand that plenty of colleges are “good enough” for this purpose.
So, like, Ivy+ are fine of course, but so are all sorts of other private universities. Obviously all sorts of LACs, which appear to sometimes be off the radar of “tiger” types but of course have been popular with many upper middle and indeed true upper class families for a long time. I also sometimes single out Wake Forest as a litmus test. I could use any number of others, but Wake Forest is among the sorts of universities plenty of upper middle class families have graduated from and then sent their kids, and if it is completely off the radar of a certain ambitious family that is an interesting observation to me.
And then there are many publics as well, flagships and also a variety of tech publics and so on. Again, lots of upper middle class parents went to such colleges, and they happily send their kids to such colleges, understanding that if you do well at such a college you can then go on to a successful professional career.
And finally I would mention the service academies, which I gather are definitely not discussed much in “tiger” circles but are certainly another well-worn pathway to ultimate professional class success among various US families.
All right, so of course when you add that all up, now you have plenty of room for the college-bound kids of the US upper middle class. And I guess it is theoretically possible that all those upper middle class parents sending their kids to all those other colleges besides the Ivy+ are absolutely miserable with their failed kids–but in practice, nah. They are mostly happy with that, again because they know it means their kids are still on track for some sort of professional success.
So to me, that again is one of the litmus tests of tiger versus not-tiger upper middle class norms. If you implicitly expect your kids to go to a “good” college but that potentially includes Wake Forest, Ohio State, Mt Holyoke, and so on, then that doesn’t sound very tigerish to me. But if you think your kids will be failures if they end up at Wake Forest or Ohio State or Mt Holyoke instead of an Ivy, that is what I think of as the “tiger” mentality towards US colleges.