There's technical possibility and then real world practicality.

For the same reason, a pure WebAuthn flow in a compliant browser could technically implement secure payment confirmation mandated by the DSP, but afaik no bank does that, and the W3C is still working on the spec.

Our governments can't even manage not to depend on Microsoft/Google/AWS (and Palantir, the US military industrial complex, Israel, ...), our banks are regularly under the fire of extraterritorial bullshit due to the USD dependence.

Being worried about consumer devices and their OS is cute, but it's missing the forest for the trees.