What I found interesting in this paper were the five facts which he presents as evidence about growth, and challenges for growth theorists. There are many firms in a market economy. Discoveries differ from other inputs in the sense that many people can use them at the same time. A calculator, on the other hand, is a rival good. It is possible to replicate physical activities.
Technological advance comes from things that people do.
What Romer is saying here is that technological advances come when people start experimenting or looking for market niches. The IBM Proprinter happened because a firm wanted to get competitive. The IBM happened because they needed another market. Many individuals and firms have market power and earn monopoly rents on discoveries. What some other theorists have implied is that it's probably a good thing for some countries to let the property rights slide for a few years, so that a country can catch up, and then put them in place to protect their developments.