I found this article by Ven. Walpola Rahula to be interesting: "". Ven. Rahula makes a case that something like the Bodhisattva ideal is present in Theravada.
And yet, it seems to me that Theravadins and Mahayanists mean completely different things by "arahant" and "bodhisattva", to the point that both groups almost always wind up talking past each other. This is only compounded by the polemical (and often anachronistic) use of the term "Hinayana".
Fundamentally, I think part of the issue is that Theravada is a sect and not a "yana", but Mahayanists act like it is a yana - specifically, the Hinayana or the small/inferior/narrow vehicle. Because the Pali Canon and Theravada in general does not speak of "vehicles", all too often Theravadins wind up on the defensive, accepting this incorrect definition, when instead they should be reframing the conversation by pointing out that the Way of the Elders is a sect, not a vehicle. Confusing the two is like saying that Zen (a sect) is a yana, or that Honda is a sports car, rather than a car manufacturer (which makes sports cars, among other kinds of vehicles).
Any given sect may have multiple yanas available to the practitioner (in the same way that any given car company may offer multiple kinds of vehicle - sedan, sports car, SUV). There is an old thread here about "" which suggest that even Theravada even has its own versions of the "Diamond Vehicle" or "Mantra Vehicle". If this is true, then it makes sense that something like the Mahayana Bodhisattva ideal could exist in a Theravada context as well.