A problem we've always had is finding other ways to drive revenue. Asset store profit we make wouldn't cover even 1 employees salary/costs, and there are ~8 of us at the moment. It's a nice thing to have to help, but will never come close to our core product.
Secondly, our strength is that we do mainly focus on our core product! Spending our time creating assets/templates etc to sell would ultimately take away from that. We'd rather just play to our strengths.