There are two things to tackle here which I’m keen not to mix up as I think their epistemological properties are quite different:

1) [the stronger one] while the scenario/narrative is a compelling one (or maybe it just feels compelling as I’ve heard it so many times), if it doesn’t have experimental/data backing I have to abandon it.

2) [the weaker one, as it replaces a narrative with another narrative within a complex system] I’ll only give the highlights as the arguments are a lot more eloquently laid out in the book; part of it is comparing the force of “many inventor nodes building on top of many invention nodes” vs “inventor nodes (with more investment individually?) building on top of fewer invention nodes”, part of it is the game theory effect of companies collectively investing less (proportionally) in R&D as the ROI from lawyers under this regime has more power, part of it was that actually, the reverse-engineering-simplicity story was too overblown and that actually the friction + domain knowledge has a stronger effect than people think (they published a paper on this). There were others, but it’s been a while now!

In many research-intensive products go-to-market costs are bigger than the cost of actual invention. You buy a pharma startup for a few million for their patents, then spend tens of millions on certification, trials and manufacturing pipelines. Your competitors would spend most of that too on the same markets. Also, true inventions are rare. A lot of stuff that is being patented is just effort spent, that a lot of people could reproduce (and routinely reproduce, then hit the patent and spend more time to find a workaround).

Indeed. Patents incentivize investment in R&D. There is an argument to be made that the scope of patentable inventions should be more limited, in particular preventing trivial patents that didn’t require substantial R&D, and maybe also that patents shouldn’t last as long.

But doing away completely with patents would certainly stifle companies’ willingness to invest in R&D. They’d rather wait for someone else to invent something they can copy.

Reverse engineering may be easy for really simple inventions, but quickly becomes so hard you may as well invent the thing from scratch. Look at USSR's domestic chip production. At one point they succeeded in reverse-engineering chips like Intel's 8086, VAX etc., but chip design very quickly became so complex reverse-engineering the entire chip became impossible. I would say if an invention can be easily reverse-engineered, then it is a simple foundational idea that should not be patented, and if it is truly innovative, then it cannot be reverse-engineered easily and doesn't need patent protections.

Then there is the fact that when something is patented, that has a chilling effect on competition, making the market less efficient.

There are also a lot of really silly patents that end up benefitting no-one, not even their inventor, but only result in needless litigation. The recent lawsuit between Nintendo and PocketPair comes to mind.

While there are cases in which patent law can help individual people profit from their invention, once all consequences are tallied, the overall effect of patent law on society appears to be negative.