Because of supply, lack of interest, or kids?
Supply shouldn't be an issue. The rate they're sustaining is just mRNA vaccines, and both J&J and AZN expect EUA soon. Logistics shouldn't be an issue either, the non mRNA vaccines are stable and can be administered at local doctors offices, pharmacies, etc.
Demand from young people is a big concern of mine, vaccination for children, and yes, possibly mutations as well. Add to that a false sense of security that vaccinated people have that'll potentially keep spreading the virus to unvaccinated people. Less transmission is not no transmission.