
Treat Writelike like a gym
You can treat Writelike as daily training that yields steady gains with the occasional breakthrough.
You can make sure your class always has a lesson assigned, and that students submit a couple of responses each day or a lesson a week or some other cadence that suits.
You can use Wrotevote or Peer Review to help make the work rewarding.
People quit gym training for lack of reinforcement, but they'll stay in a sports team because there's a social game every week, and they enjoy playing with their friends.
Same with Writelike; the training is hard work, but the social performance is rewarding.