Neither is it clear that any elliptical galaxies are ellipsoidal. They are called "elliptical" because they appear, in two dimensions, similar to ellipses. In fact, most are disks, which may be nearly flat or could be expanded out nearly to spheres. That does not produce an ellipsoidal shape.
Interesting, Chris. It is just possible that I'm more of a galaxy nerd than you are, and I haven't heard the claim that most elliptical galaxies are disks.
The entire class is defined based on the fact that they are observed to have elliptical shapes in projection, ranging from circular to cigar shaped. Outside of rare cases that actually are significantly asymmetrical (which isn't dynamically stable for long periods), that implies most are disk-like and how we see them depends on their angle with respect to us. Call that "disk-like", or "oblate-sphere-like" or whatever, the point is that most have a circular cross section along one axis.
My impression is that when I look at galaxy clusters full of elliptical galaxies, the largest galaxies always appear to be (fairly) round. If some of them are disk galaxies, we ought to see some of the largest ones as elongated disks. Yet we don't, in my opinion. So may I inquire about your sources that say that most elliptical galaxies are disks?
As I hope I made clear, I only use "disk" loosely to describe a shape that is circular on one axis and extended along the perpendicular- either a small amount, meaning that the object is quite disk-like (producing a cigar shaped galaxy when viewed at an angle) to spherical (producing a circular galaxy when viewed from any angle). An elliptical galaxy is very similar to the bulge of a spiral galaxy. Over time, any flat galaxy will evolve to a spherical shape, since that's what large, gravitationally bound particle systems do.