That's not the point, the point is that the effort required makes it harder to innovate and that not only does that limit competition but it also enable proprietarism.

In a perfect world you could just e-mail the data without any concerns of authenticity, privacy, robustness etc. But you can't, so you would have to bring in a huge firm that is going to spend a lot of money and effort getting everything right or at least certified. Of course with all that effort they now have a huge incentive to keep thing proprietary since they want to recuperate their cost and the large barrier to entry make it even more advantageous because there will be little competition.

Innovation often requires COTS components to be available at a sufficient standard. No one would doubt this when it comes to something like AWS or how Tesla could make such a high level car in a relatively short time. Of course if you question the state of software you get downvoted into oblivion without reason on HN.

And if it wasn't clear, these (proprietary) systems very much exists.