All the Contis that I have purchased & used, have not cracked.
Where are these who get such; how are the bikes/tire place/stored??
In the shade? In the sun? For how long in the sun??
Contis will survive in the sun longer than any other tire. As shade is not always to avail, for bicycle parking.
Contis also are the best traction (general asphalt-water & gripping over oil contact), for driving in the rain (as most cyclists are too sissy to do such driving).
Over-inflation of PSI of Continental has only given me better driving traction. One simply has to be a betters killed cyclist before doing so.