There are a lot of people for whom the 'small' barrier to entry of dealing with state bureaucracy is much larger than it is in your world.
Voter ID would be important, but unfortunately, the Republican Party has repurposed the concept as a tool of oppression rather than a way to secure the vote. People are rightly wary of the idea because of this, and will continue to be wary of it until free and no-hassle IDs are available to everyone first.
> However, for most people in America I would wager that this is not the case at all
Most? Probably. But "most" doesn't matter. Voting is a fundamental part of the democratic process, and "most" still leaves millions of people in the lurch. Make it "all" and then I'll stop being upset about it.