My concept of a Malthusian economy involves two characteristics. First, living standards are negatively related to the size of population. This would occur if we had some sort of fixed factor of production. Typically, one might say it was agricultural land, but you could just say resources if you like. It isn’t even important that they are truly fixed. So long as the resources are inelastic, whether due to a physical limit or because bringing them into use is prohibitively expensive, you’d satisfy the first characteristic of a Malthusian economy.