Captcha have audio versions for the blind, no?
Though if you aren't considered suspicious, image captchas are way less ridiculous, too. The scoring system goes all the way from .1 to .9, but usually you're either in one or the other category based on who knows what (probably mostly ip addresses, but Google doesn't tell us so who knows?).
So in the end the service is mostly just something that arbitrarily classifies users as one or the other, bots can absolutely solve them when classified as "probably human" and they're impossible for humans when classified as "probably bot".
If you want to actually present users a challenge to verify they're human, you're even better off giving them something like captchouli[2], or just a good old scrambled letters on a picture thing (which is what Google uses for their login as well, BTW). hCaptcha is also a great alternative (anything is, really) since it's still mostly about classifying users by making suspicious ones solve challenges. reCAPTCHA is absolutely not, it judges you before the challenge.
And that's fine, some websites want that. It's their choice, I'm not mad if they ban me for not wanting to be tracked, it's probably for the better. What does make me angry is that reCAPTCHA is advertised falsely, that the challenge is a joke and a crime against humanity at once, and that despite that, people seem to believe that it's the challenge that is magically blocking the bots without realizing they're also blocking legitimate users.
My guess about the future path is as follows: your government ID allows you to authenticate to generate a keypair you can use online for services such as Google and Facebook. It would include things such as a nickname, and an e-mail address as a derived public/private keypair you are able to use, including a scope (domain). Then, only such authenticated logins get full access (they are not going to phase this in like a wrecking ball, it would be slowly). Its perhaps a tad dystopian, but it has its pros and cons, and websites like GAB will continue to exist on darknet.
A centralised ID system is one solution for authentication online but it's far from ideal.
A much better system is a decentralized pseudonymous ID system where getting an ID is in some way expensive but still anonymous, e.g. proof of work equivalent to $5 in cloud CPU time. Then legit users can create an ID once and use it indefinitely, but also create as many as they like and replace them as often as they like for a relatively low price.
Meanwhile spammers pay $5 for an ID that only lasts ten seconds before it gets banned and has all its messages retroactively deleted, so they go out of business.
It's a tough nut to crack. It goes under the term proof of individuality in terms of Blockchain.
This is always the claim but I don't really see it. Obviously if you put something on the internet then you disenfranchise anybody without a computer and an internet connection. But who is it that can afford a $50 device and a $10/month internet connection but not a one-time cost of $5 worth of CPU time?
There's always a way around incentive based methods.
If they had that amount of CPU time they would have the opportunity cost of using it to mine cryptocurrency instead, so it's still costing them $5 per ID.