They exist. But they don't support Android apps that are unfortunately necessary. For example, any phone without WhatsApp or banking apps support is dead on arrival in Europe.
Though I see signal usage creeping upwards. Maybe just my circle
"EU Age Verification Project Mandates Hardware-Bound Attestation"[1]
[1]: https://www.reddit.com/r/Android/comments/1vds3jm/eu_age_ver...