I havent had a pair of the alpha burly’s since the early 2000’s…maybe 2007 or so? Anyway, I wear rubber boots 300 days a year running my dog, so generally wear thru them very fast. I also had a pair last me 2 years or so (the neoprene in heels always wears through fast, but the outer was leak-free at least), and the replacement cracked in the ankle and where the toes crease within 6 months. Ditto for the next pair. At the time I heard people say it was the rubber compound, and that they had gone to cheaper plastics that didnt last. Either your old pair was very old, or perhaps its simply the difference between batches of material that isnt really precise?? Who knows.
After destroying 2 pairs in less than a year I went to leather-lined le chameau boots. Much better hold on your foot, no heel-rub from the neoprene lining wearing out, less sweaty, and made of real rubber so I was getting 4-5 years out of a pair before I had to replace, making the astronomical price tag actually cheaper in the long run. Ive since also gotten a pair of the alpha agility boots in order to have some insulation from the neoprene, which are on their second season. I would say they are MUCH better boots than the alpha burly’s. Maybe try a pair of those instead.