I invite anybody who thinks this is a mic drop to pull down the Tranco research list of most popular/important domains on the Internet --- it's just a text file of zones, one per line --- and write the trivial bash `for` loop to `dig +short ds` each of those zones and count how many have DNSSEC.

For starters you could try `dig +short ds google.com`. It'll give you a flavor of what to expect.