Do they seriously only pay 25 cents (or so) per domain? Why has there not been some disruptive registrar selling .com's for, say, $4? Whatever the operating co

Do they seriously only pay 25 cents (or so) per domain? Why has there not been some disruptive registrar selling .com's for, say, $4? Whatever the operating costs of being a registrar are, it seems like they should be no more than $1/domain-year. So if a registrar dropped their prices to $3 or $4 and grabbed half the market out of it, they'd post huge profits. Obviously those numbers are just guesses, but I highly doubt that it really costs $9/year to host a domain at scale.