The problem is implementing that in a way that doesn't disenfranchise a lot of people. Most or all countries that have the kind of robust national ID system for such a system also make sure it is easy for every citizen to get the necessary ID.

Such a system could be added to the US without too much disruption if we did it gradually, say making it only apply to people born after 2030 so there is time to get all the support infrastructure in place.

Doing it quickly, and making it apply who grew up in a US without anything like that, would be a big and probably expensive effort. None of the proposals I've seen Congress talk about, or seen states talk about or that states have passed, have addressed this.

They say it is actually easy to get the required ID, but when you dig into the documents needed to get it if you don't already have a government issued photo ID it is a lot harder.

A certified copy of your birth certification is usually good enough...but most states require government issued photo ID to issue a certified copy of your birth certificate. Oops.

Also, for many older people, it can be hard to find where to go to get a birth certificate. That's all handled by the states, not the feds, and at the time many older people were born many states just recorded those records at the county level.

There are alternatives that allow can work around the lack of a certified copy of your birth certificate, or that can work around needing a government photo ID to get the birth certificate. They involve secondary documents, such as school records. Those don't usually have difficult ID requirements to get, but are even less likely to be centralized. You might have to go to the school district to get the records. For an older person trying to dig up old elementary or middle school records to bootstrap getting an idea that will often be difficult, even if that school district is still around and somehow the records haven't been lost.

The current system does in fact work well. It should be replaced with a stronger that could stand up against larger and more well organized adversaries than it has had to face before, but it is not urgent, and we have the time to do it right.