Why are puncture-resistant tires not used in professional races?
To a racer, rolling resistance and handling top the list; durability is far down the list. The coefficient of rolling resistance (Crr) for a racing tire on typical French or Italian roads used during a Grand Tour is about .004, or even lower. The Crr of a puncture resistant tire can be > .01. Crr scales like gradient, so the difference between Crr's of .01 and .004 is like constantly climbing a slope of .006 (=.01 - .004), or slightly more than half a percent. On a 150km stage that's like climbing an extra 900m hill. No racer willingly gives up that much advantage, especially when there's wheel support from either a team car or neutral support (and for team leaders, a wheel swap from a team mate) should you get a flat.