According to Meltzer, Austin was the biggest draw in the business between 1998-2001, in other words up until the point of the botched heel turn that hurt his drawing power. Dave says that no one before or since has matched Austin's peak drawing power during those years.
Dont get me wrong, Rock is one of the biggest draws in history, but at no point did Rock surpass Austin's peak drawing ability. Rock never had the impact on the business that Austin did. The most he ever did, even in 2000 was take over the reins of an incredibly hot company and keep it going (with a lot of help and good fortune of there being no strong competition from WCW). Austin took over a cold company and made it white hot. Rock just had to keep things going.
To thrive in an extremely hot company with no competition, takes less individual drawing power than it takes to make a cold company white hot in the first place, particularly in the face of huge competition from WCW.
Rock never matched the increases Austin brought in terms of ppv, ratings,merchandise, etc.
Also, it has been widely reported and accepted that the Austin-Lesnar situation in 2002 was because Austin publicly criticised the creative team, which Steph was part of, and they booked him to do the Lesnar job out of vindictiveness, not good business sense.
Dave also said that Rock's effect at the wrestling box office when he returned in 2001 was a big disappointment.
In 2002 Rock headlined Mania with Hogan and lost hundreds of thousands of buys from the year before despite an unprecedented amount of money being spent on advertising in 2002.
After Mania, Rock left, and the first show without him increased business from the year before. When Rock came back, every show he appeared on lost business from the year before.
In 2003, Rock came back and created the Hollywood Rock character, but as entertaining as many found it to be, the character never gained traction with the ppv buying public, as every show Hollywood Rock wrestled on lost business from the same show the year before.
So, basically if the Rock is your favourite, that's cool. Just don't portray your preference for Rock as meaning that he was factually the biggest draw of all time. If you want to believe that, fine.
But realise, there are many people like Meltzer and Keller who have researched extensively into the matter who don't agree with you.