From an economic perspective I find this very inefficient. The notion of 'universal' design would neglect the fact that there are very specific design requirements based on said discriminations. By designing one 'universal' product for say the rich/poor instead of one product for each, in most cases, you'd end up with a portion of the rich unsatisfied by an inferior product respective to expectations and an unsatisfied poor because its too expensive for them. In fact I think the cases where this does and should hold true (things like 'soda') are a rarity.
A market exists for designing things specifically for a certain demographic, and markets are where capitalism thrives. Why this this one-size-fits-all model better than a call to designers to start exploring neglected markets and making unique products for said markets?