As I understand it, the Apple devices have a secure element with initialization keys written at time of manufacture, which are then personalized to the user with a new/unique set as part of a registration, but verifiable as having being provisioned, so there is a cryptgraphic chain of trust going back to the manufacture of the secure element.
Android is an operating system for a bunch of OEMs who don't have secure elements in their devices, and even ones who do still exist in a fragmented ecosystem where their verification doesn't include ones outside their models. Modern chips have a similar feature, but the key management between manufacturers is an unsolved business problem. There are technical ways to solve it, but higher level interoperability beyond enforced standards has never a high priority for OEMs. The economics haven't been there.
You could make an inferior one for Android devices, but it likely wouldn't be sufficiently secure to handle payments, credit, taxation, fines, social compliance scores, and other use cases for identity. Identity security needs to be strong enough to be used as a stick, and the only carrots it offers are those whose scarcity is artificially managed.
Realistically, if you are attending a university, the cost of an Apple device can just be priced into your loan, and strategically, making university student products consolidate Apple's dominance of the middle class market and up, and as a status symbol of societal membership, sort of how Facebook started in the college system.
I'm skeptical of digital identity companies (as distinct from authentication services) because to me their entire business model reduces to Hollerith machines as a service, so YMMV on this view.