why couldn't a blockchain have built in identity (through verifiers) to ensure 1 account per identity, and a voting system? Is there something about voting that

why couldn't a blockchain have built in identity (through verifiers) to ensure 1 account per identity, and a voting system? Is there something about voting that wouldn't allow vote records to be public? System could automatically just ban anyone who gets below a 2 from 3 separate drivers, or something else ... there's ways... it's not a hard problem to solve...