>We know how much disk costs. It is a rounding error for the overwhelming majority of people and the overwhelming majority of apps.We know how much disk costs, but at any given moment a certain non-negligible share of businesses will be working with very old equipment in some of their branch offices, self-service terminals, factory floors, labs, etc.
I agree that 17 MB will rarely be a show stopper in isolation. But resource consumption is critical if Microsoft wants .NET to be a universal solution for business computing needs. Memory is far more likely to be the bottleneck in my experience.
If a company has modern equipment in 95% of their locations, but the remaining 5% are difficult to upgrade for some reason (cost of disk is unlikely to be that reason), then those 5% will determine which technologies are even taken into consideration.