Every so many years they have to change the tire-sizes or some other feature so they can tell everyone that their current bike is outdated and they have to buy a new one to remain "competitive" and current. This is complete hogwash as 90% of riding a bike in fast or technical challenges is the rider, the bike makes little difference as long as it is in good shape. Records were set on MTB courses with 26" wheels back in the 1990s that 99.999% of the riding population will never be able to get close to even if they are riding a $15,000 E-MTB.