My completely naive guess would be that venom is mostly too slow for creatures of this size compared with gross physical damage and blood loss, and that getting close enough to set claws on the target is the hard part anyway. Venom seems more useful as a defensive or retributive mechanism than a hunting one.
Why don’t lions, tigers, wolves, crocodiles, etc have venom-tipped claws and teeth?
(Actually, apparently many ancestral mammal species like did have venom spurs, similar to the male platypus)
My completely naive guess would be that venom is mostly too slow for creatures of this size compared with gross physical damage and blood loss, and that getting close enough to set claws on the target is the hard part anyway. Venom seems more useful as a defensive or retributive mechanism than a hunting one.