I think that's not how OP was thinking about it. People may not be able to create a startup--or even think to do so--because someone else's patented product cou

I think that's not how OP was thinking about it. People may not be able to create a startup--or even think to do so--because someone else's patented product could be unavailable to them (due to monopoly pricing), not because they feared that their final product wouldn't be strongly patentable. The number of people who are prohibited from even being be able to obtain the knowledge to innovate is uncountable. Of course it's a trade-off between incentivizing innovation on one hand and enabling the spread of knowledge on the other, but needless to say the number of people who didn't create a startup because of patents is inestimable (not inestimably high, just inestimable).