I guess I don't understand why if those things were possible why UPS wouldn't already be doing it? What is Uber's secret sauce that would make them be able to solve that problem?
Regulations governing licensing, employee welfare, public liability, and other such, which Uber currently works around (but might not be able to indefinitely, people are looking very carefully at the situation).
Even ignoring this difference, UPS might not consider the profit margin worth the risk and the cost of the up-front infrastructure changes.
UPS is a shipping company first and a technology company second. Uber is a technology company first and a (taxi|courier|etc) company second. It's a difference in mentality.
