why don’t they have a bot of Karpov?
Sort:
Why don’t they have bots like Karpov or Fischer or Kasparov?
I assume you need the person's permission to make them a bot, so maybe they did not give their consent. Also Fischer is dead so the permission process would be long and complicated.
They are probably focusing on their monthly bots as it takes a long time to develop a bot and they have bots every month.