There's tons of highly specialized vertical market software that will basically never have open-source alternatives. Every industry has a few examples. I at least know of the high-end CAD, FEA, and CFD software used in certain branches of engineering. See Ansys, Autodesk, etc. The reason why is that building this type of software correctly requires an immense amount of domain knowledge. That type of knowledge doesn't come together in a useful way without a lot of money.
Such software also doesn't get used enough to be trustworthy as far as results without some other big companies using it to do things with and testing the results. What company is going to trust their product designs to the results of a bunch of open-source code with no company standing behind it?
Such software also doesn't get used enough to be trustworthy as far as results without some other big companies using it to do things with and testing the results. What company is going to trust their product designs to the results of a bunch of open-source code with no company standing behind it?