The option for a reasonable name still exists (and site owners don't have to arbitrarily confiscate it to give it to more PR-worthy people), it just might be a slightly longer reasonable name with a disambiguator built into it instead of a common first name or cool dictionary word, and you get a reasonable URL as a bonus. I'd probably rather be found at instagram.com/johnsmithspringfield than instagram.com/jh9fjhfgjhg (or 'search for "John Smith" and scroll through 300 entries') anyway.

Of course with unique identifiers you probably don't get to call yourself elonmusk, POTUS or amazon