If a blocker prevents repolarization, will the neuron be stuck in a depolarized state forever?
The voltage-gated potassium channels are there only to swiftly repolarize the membrane potential. Ultimately it is the Na,K-ATPase that has to pump the various ions back where they belong (Na out, K in), also when potassium channels are active. So when the potassium channels are blocked, the Na,K-ATPase will restore the membrane potential, albeit in the order of seconds instead of milliseconds.