Citation needed. Open source development proves that IP restrictions are not necessary to produce engineering development. And look at 3D printers. Their price went from $50k to $25k after the first ten years on the market, when they were under patent. When the patent expired, development exploded and ten years later the price had dropped to $250. One of the most popular 3D printers in the world, the Prusa i3, is completely open source. Certainly one cannot say that "without IP... everything grinds to a halt" when faced with these examples.
I’m not saying the economy can be run by volunteers. Engineers at Prusa are not volunteers, they get paid. And they make their designs all open source. They do not need intellectual property restrictions to make their product viable.
EDIT: Here is an interview with the creator of the first hobby 3D printer. In Europe, unlike the US, research projects are allowed to violate patents. He explicitly calls out the expiration of the patents as the thing that allowed them to expand beyond just research. https://www.3dsourced.com/interviews/reprap-dr-adrian-bowyer...
“We never had any problem with Stratasys complaining about what we were doing, there was only one thing that happened: we got a letter, very nice and very polite, very conciliatory, from one of their legal people saying they had a trademark on the term FDM and could we please not use it, so immediately I invented an equivalent term, which was FFF and we just edited everything on the site to that instead. That’s the only time they tried to interfere or anything else with the project. They never complained we were infringing upon their patent, which we weren’t of course [research projects in Europe can research a patented technology for the purpose of improving it without any kind of patent infringement], and we weren’t selling any machines.
“Once the patent expired in 2009, of course the project was free to do whatever it liked. Coincidentally, that was just a few months after we got the first printer working. It all came together fairly nicely in that regard.”