I kind of think the whole "long race" thing is rather silly.
Yes, it's true that over time, the better player will usually prevail, but as we all know, pool isn't really a game where your ability stays static. You can have great days and not so great days. Beating someone in a race to 100 over 3 days, may mean you were the better player, but next time the score may reverse. The long race does kind of mess with your mind a bit, and no doubt the psychology of the player plays a bigger role in these. Some players can wear you down with their playing style and antics, more than they actually outplay you physically. I used to play a lot of long races with regular playing partners, and let me tell you: They didn't all go in the favour of the stronger player. Sometimes someone just got on a roll and won tons of games in a row, and it became impossible for the other to catch up. Some people just give up when they are behind by 20 in a race to 100. Doesn't mean their raw shooting ability is bad, but some people don't love to grind.
A long race is a test of stamina, psyche and also ability. Nobody can keep their consentration at peak levels for that long, so usually it's also a test of physical conditioning. The player who is maybe a little chubby, not well trained, may find him or herself at a disadvantage from that alone, as he or she may not be able to keep their game up to it's normal base level over a long period of time.
I'm really not all that interested in those aspects of the game. I like to watch people play at the peak of their ability, not watching their B-games over 12-14 hours. A race to 15 is more than adequate to let rolls even out, IMO. I don't want to watch Usain Bolt jog! I want to see him sprint!