How do you reconcile a patentless world with things that require massive R&D budgets? Like it or not many industries require very complicated ideas that are extremely expensive and labor intensive to generate the idea.
For example, new pharmaceuticals (of which there are very few being discovered) take over 10 years of R&D and cost multiple billions of dollars to whittle down ~10,000 candidates into a single government approved drug.
But once that single drug has been identified from the haystack of failing options, and rigorously tested, and trialed in humans for years, recreating that molecule is quite trivial. The actual production is very cheap compared to the fact it took thousands of people billions of dollars over 10+ years to get there.
This is just one example of how ideas can be very expensive to develop, but very cheap to copy.