For those that don't have the luxury of having an education combined with training in a relevant skill, that middle ground is just wishful thinking.

Conceptually possible, but in practice what market forces ensure that such a group exists?

I know a non-zero number of people that both work paycheck to paycheck and also make work the most important part of their lives. That's not to say it's mutually exclusive with 'neither' group, but I don't think it's impossible for the 'neither' group to shrivel into non-existence.