Adam Smith and Karl Marx quotes relevant to whether writers are working class

Thinking about whether writers and freelancers are working class brought me to two quotes, one by Adam Smith and one by Karl Marx: There is one sort of labour which adds to the value of the subject upon which it is bestowed: there is another which has no such effect. The former, as it produces a value, may be called productive; the latter, unproductive labour. Thus the labour of a manufacturer