I'm an individual, and I really don't like administration. Why can't I just register and own a domain rather than effectively paying rent to exist?

Your point about business operations is totally valid, but business is just one sort of human activity and shouldn't be the yardstick for everything else. Most of these blogs on blogspot.in were likely just personal journals. Domain registration seems like the sort of thing a public blockchain would be ideal for in comparison to a centralized registrar.