Philosophy but no economics

Can this be right?

When discussing the contribution to economics of the ancient Greek philosophers Edwin Cannan writes,

The fact that these ancient philosophers were not and could not be economists in our sense of persons who are interested in and think and perhaps talk or write about the material welfare of mankind. They professed to be concerned with higher things, and if they were not always so in fact, it was because they thought of themselves rather than because they thought of their fellowmen. Their State, of which they made so much, covered a contemptible little district with one small town in it and a population of which the great majority were not citizens but slaves. It is impossible for economics to develop in such an environment.

Is it really impossible? Even within such an environment there are questions to do with resource allocation, questions to do with the hows and whys of production and distribution, problems to do with the supply of public goods, issues to do with the supply of money and the fiscal behaviour of the, albeit small, state, questions to do with international trade and so on. Can't such problems give rise to economics? And if not then what are the prerequisites for economic thought to develop?