Why is private property important for technological progress to occur?

Private property includes the right to intellectual property. This means that you have the right to claim your inventions, and the income associated with them, as your own, giving you an incentive to invent new things. Technological process would be less lucrative to the people driving it if they were not guaranteed ownership, at least for a certain period of time, of their newly developed intellectual property. This would create less incentive to innovate, resulting in slower technological progress.