They may as well have for many people.
When a copy of a person's driver's license and the last 4 digits of a person's social security number is required to be sent through the mail, a lot of people aren't going to vote by mail.
Many older people can't go get their driver's license copied. Many other people are like me and will not put such information through the US Mail. It's not secure and a person can steal an identity using that information.
Mail in voting has been made so hard in some states that people who have voted that way for years, will not vote anymore.