I'm a proponent of these ideas. Patent duration as a function of private capital spent? It would have to be immune to "profit-shifting" but maybe that could be a good alternative.
After posting I did consider the lone software engineer who comes up with a great idea, creates an app, and his app is then copied by Google who has much better marketing and distribution resources.
If patent duration was a function of investment in R&D, this software developer would be SOL because he invested little into his "eureka" idea.