If the attacker only got a hold of password hashes or something, then it's true that they'll only be crack a limited amount. However, if that were the case you'd expect the people with easy passwords to get hit first, because an attacker would presumably go through the common words in the wordlist before the uncommon words, and finally a brute force search. Doing attacks in this manner would maxitimize the speed at which you gain access to accounts. However, this doesn't seem to be the case? You'd expect all the people with easy passwords "p4ssw0rd" or whatever to fall first, and in great numbers. This doesn't seem to be the case because many people seem to be swearing their passwords were unique/secure.

If the attacker got a hold of the raw passwords, then the speed of compromise could be easily thousands of accounts per hour. Just set up a bunch of TOR clients and bruteforce over that, or pay $10 for a few leaked VPN account credentials.