Apple and Google have dominated the smartphone era because of their huge bases of apps, and as growth and profits in handset hardware slip away, they will need to sweat their software assets more aggressively. The past week has seen both Apple and, reportedly, Google making changes to the way they share revenue with developers in their stores. The top line is that both giants will reduce their cut of a developer’s revenues from sales in the App Store or Google Play. This seems geared to rekindling programmer excitement about the stores and ensuring they remain the primary places to sell applications. There are other motivations at work in Apple’s changes. It will reduce its cut of revenues from 30%…