Ok let's look at this.
Ok if you really think about this, what is the biggest difference in any given tournament between players at this level? Mental position. or State of mind.
These players have systems that will give them correct alignment on almost every shot, or experience it doesn't matter the question is what makes someone perform or dog on any given day?
In a standard tournament format, players are under tremendous pressure, if they lose a single match, they then can only lose one other match if they want to advance any further, not so in this format. Also, whatever level in the tournament they are when they lose that first match determines how much money they are going to get. Again not so, so that means there wasn't as high a per match level of pressure here as there is in most tournaments.
Second for the HOF'ers, sure there is some pressure to make sure that they don't look like has beens out there, but they're probably not focused on that so much as they're comfortable that they are about to have one of the biggest single paydays many of them have seen in their careers. 30,000 minimum is nothing to shake a stick at for losing. So they are likely more in a mindset of being well into the money than being a mindset of the start of a tournament, and since mindset is the biggest difference in the way a tournament turns out at this level of play, I'm not sure that the HOF'ers aren't at an advantage instead of a disadvantage.
Some of them have been out of major level play for a little while and I don't expect them to necesarily win but I wouldn't count them out quite yet either.