> Any piece of valuable software will get a free version after some amount of time.

There are still plenty of areas where this isn't true. Or where the free versions are so far behind it may as well be true.

I work on CAD software that integrates with Catia, NX, and Creo, and the pro CAD software is light years ahead of the free alternatives. And even if the free stuff catches up, there's practically zero chance the biggest users will switch from what they're currently using. CAD lock-in is tricky. A lot of times the different CAD systems target different niches, so it's not just file format lock-in, but that a certain CAD system is better for making planes, or designing for CNC, or whatever. And most companies have automation that integrates with their particular CAD system. And the parts have to be read by newer software for decades and produce identical results, or they won't fit together right.

Some of the vendors release free versions, but they're not open source, and they're only there to steer people towards the paid versions later on.