Because through blood, sweat and tears we've landed on a system that is based on market-economics coupled with welfare state to provide a safety net. Changing any of that would require a wholesale destruction of our current system and is no better than the Russian revolution. Our system has a lot of slack. You can adjust market and welfare policies across elections. There's a lot you can do within the system - your problem seems to be that policies you like are not pushed through the system ... but that's Democracy for you. It takes effort and negotiation to make societal level changes.

>So I guess what I want is less of a religious view of the social systems and more of a engineering view.

Social systems are not engineering systems. They are messy because they are fundamentally composed of messy individuals with historical baggage to boot. You cannot create a clean top-down plan without it looking like Soviet-style communism. Democracy is messy and requires give and take and negotiation, compromise, and horse-trading between all the thousands of different stakeholders and groups. You cannot clean that up with an engineering schematic. You're falling into the trap that all ideologues fall into.