That's a s(p/c)ammer's dream if there's a lesson to be learned from the.tk experience.
I think this should fall on governments to create such a system for their citizens. A cheap web.de or website.au, would be very practical.
Also I think national regulators would have more legroom to control such domains as they can exclude non-residents and avoid to deal with international rings.
On a personal level, I'd suggest buying a short domain (I own a couple of ab.xy ones) and use that as a personal tld of sorts.
And with Cloudflare, you don't even need to manually configure the DNS settings or let's encrypt.
Having a website up and running in 10 seconds without having to go through the process of registering a domain is such an amazing experience!