> Hasn't this already been true for years?

No, not every law has provisions for free IDs and even when "free" IDs are offered it still costs people money
https://today.law.harvard.edu/wp-content/uploads/2014/06/Ful...

> Is there any voter ID requirement, or even a proposal for one, that doesn't accept drivers' licenses?

Millions of Americans don't have a drivers license or any form of government issued ID
http://www.brennancenter.org/sites/default/files/legacy/d/do...

This is pretty common in elderly and disabled people who can no longer drive. They often see no reason to keep renewing a state ID. If we had a national ID card that every citizen was required to have from the time they were children until the day that they died it wouldn't as big an issue, but that's not the case. Groups that help support the elderly and disabled have been dealing with the problem for many years.

see also:
https://www.aarp.org/politics-society/government-elections/i...

> You can get that at 16, and most people get it well before 18, the minimum voting age.

Most people can get an ID, but doing that might be extremely difficult. It's getting better as local governments increasingly move services online but historically the US hasn't been so great about record keeping or making the needed documents easy to get. The first time I had to get a state ID I first had to travel across the country to the county in which I was born and hand over a stack of other documents I'd spend a bunch of money and effort to get my hands on and then still pay a fee on top of it once I got back to my own state.

> Can you link to this research? In particular, is it making the assumption that people who can get an ID would just choose not to for some reason? Because I can't think of anyone who's allowed to vote but not allowed any form of ID that would let them.

This isn't new news. There are literally years of research into the problems with voter ID laws in the US but I'll link to a few studies if you'd like more information. The fact is you don't have to make it "impossible" to get an ID to make it disproportionately difficult for certain people to get one. The GOP has spent decades working to make it harder for "the wrong people" to vote in order to gain an unfair advantage. Court rulings have often found that their attempts to prevent Americans from voting were discriminatory and placed an undue burden on various groups. Even concluding at times that this discrimination was intentional. see this one for example:
http://electionlawblog.org/wp-content/uploads/20141009-TXID-...

I feel our democracy depends on us doing our best to ensure that every American citizen has equal access to the polls. The laws in Texas right now are having an impact on legitimate voters there, especially with disabled voters because communications hasn't been clear, voters are confused, and the deadline for requesting mail-in ballots is weeks away. The restrictions they put in place in Texas were not balanced by the burden it would place on the Americans least able to carry those burdens and now American citizens feel their right to vote is in jeopardy and they are correct. It's disgusting that such a fundamental right is being taken from people just because the GOP thinks it will win them more elections.

For what it's worth, I'm not against ID being required to vote. I just think we need to make sure that those laws also keep things fair. Whatever the barriers to voting are, they should be as equal as possible for every American citizen who is eligible to cast a vote no matter what their race, age, area code, or income level. Anything less than that is an attack on our democracy.

Research on the topic:

http://ippsr.msu.edu/research/voter-identification-laws-and-...

https://www.bakerinstitute.org/media/files/files/e0029eb8/Po...

https://www.tandfonline.com/doi/full/10.1080/21565503.2020.1...

https://www.journals.uchicago.edu/doi/10.1086/716282

https://journals.sagepub.com/doi/10.1177/1532673X18810012