I didn't realize it was so few. My own state doesn't require voter ID. However it looks like the states that require ID tend to be smaller, and many larger states don't require it. 41% of the US population live in states like California with no voter ID laws, with an additional percentage in states where a photo ID (as opposed to a bank statement or utility bill) is optional:

https://www.politifact.com/factchecks/2022/jun/13/nikki-hale...