I am sorry, but I am not sure what you are trying to say. Any warrior class that doesn't spend serious time honing their skills will be quickly overthrown by angry peasants, who feel that they're not getting their money's worth for their taxes. That is provided the warriors of the neighbouring tribe won't do it for them. Celtic and Germanic tribes were often at a state of low-intensity warfare, so lazy warriors wouldn't last long.

Unless you are saying that "professional warriors" (which I think a bit of a misnomer anyway) don't contribute to the labour force; but how's that different from a regular standing army?