Personally, I've never warmed up to long races. Hence, I disagree with you. Long races aren't getting boring, but have, instead, always been boring.
Endurance and stamina are not what great pool is about and in the heat of the toughest battles, nobody is afforded a chance to size up and gradually get comfortable with an opponent. Great pool is about winning against a variety of opponents having a variety of styles. Few are good enough to do it with any consistency, and that's why the same guys seem to win the biggest titles over and over.
Long races are unbearable to this fan, but I'll defer to those who enjoy these marathons. If many enjoy it, then having these marathon matches serves a purpose. That said, however, I don't know many people who will watch these snooze-fests from beginning to end, and I know a lot of fans.
Regardless, best of luck to these two superstar players.