That's a good counter-argument which I agree with. I was looking at the issue in terms of voluntary consumer behavior (visiting theaters, buying TV or hifi equipment) and industrial supply rather than public good considerations. Where limited resources are allocated by government as (ideally) neutral broker we should certainly prefer openness.
There is an argument for patent protection as innovation motivator, but lockup periods are more likely to lead to runaway market dominance due to preferential attachment. Where there's a monospony (like government as owner of spectrum) that's probably going to lead to negative outcomes.
Thanks for widening my perspective on that issue.