Putting "#ifdef PROSUMER" or something to this effect into the source code shouldn't be too costly. Disabling existing functionality is easy and it feels like cheating even if it's called "market segmentation".
This is what developers like us tend to think. But consider this: the development cost of the sodtware does not change much in order to create feature reduced versions of most products. But if you are in a small market where the volume of expected sales for the full version of the product can barely lead to proftability, creating a cheaper version for a higher volume market is a sound business strategy. This would not work with a single undifferentiated product.
I'm not saying that it is not a viable strategy. But it needs to be taken into account that tech-savvy users will not see it as a fair play, and probably will not think twice before making the most of a cheaper version.