Perhaps.

> and he has no chance of winning the general election even if he were nominated.

The national head-to-head polls I've seen that have included have him beating all the Republicans he is polled against (Trump, Bush, Walker, and Rubio), in some cases by wider margins than Clinton does in the same polls. That's not to say he would win the general if nominated, but I'd certainly expect more than mere assertion from someone who wanted me to accept their argument that he certainly would not do so.