There are no studies because the only data set we have is the world we live in, where all the wealthy nations have some notion of copyright.
It seems obvious that IP provides some incentive to create, although how much is completely unknown. It also seems obvious that even in a world with no legal protection, people would still want to create, though again, how much is unknowable.
That's true, though it should be possible to study the effects of the Act of 1976, which extended copyright duration in the US from a maximum of 56 years to life of author + 50 years.
And it seems this was done:
"Despite the logic of the theory that increasing copyright protection will increase the number of copyrighted works, the data do not support it. Instead, our findings demonstrate that the historic long-run growth in new copyrighted works is largely a function of population"
That also doesn't seem surprising in the least, though some properly incentivized individuals might feign surprise. Using the same gut logic, very few people are thinking 100 years in the future when they decide to take on a project. 56 years seems long enough that a creator would be able to work without worrying about getting ripped off.
An argument could be made that traders at large holding firms would value IP more highly with a longer term, thus allocating more money, and incentivizing production, but there are so many links involved that I seriously doubt much of that could hope to make it back to the artist.
Anyway, I was just responding to the implication that a lack of objective data is enough to seriously consider abolishing copyright altogether.
At my former employer they started getting massive numbers of returns on a product they sold. We exchanged hundreds of the devices and when the numbers got unbearable we started diagnosing the problems. Some returns, mainly from faulty installations, were expected but hundreds was unprecedented.
They noted out-of-spec components on the boards, counterfeit components, and slight manufacturing defects.
This led to months of back-and-forth, often very heated, bickering between manufacturing, quality control, the service department, distributors, component suppliers, dealers, and the engineers who designed the product.
Eventually it was determined that cosmetically-identical boards were being manufactured by someone in a country that rhymes with Dyna and had made it into the supply chain.
The company then spent hundreds of thousands of dollars on a holographic label printer, and hundreds of thousands more on personnel, procedures, and specifications to attach in-house printed serialized holographic stickers in predetermined locations and orientations that varied based revision and board serial number.
We also completely changed how we sent out new boards, implementing an expensive process where every board was tracked from production to installation, frustrating many of our distributors.
This was a small/medium-sized privately-held company in the commercial/industrial sector. We estimated that almost $10 million was spent honoring bogus RMAs (which they continue to do), determining the source of the RMAs, and implementing a solution to reduce future RMAs.
If that $10 million had not been spent fighting someone ripping off my employer's IP, at least one and probably two new products could have been developed, considering that entire teams of people, from Management to Engineers to Technicians, were redirected to work on the RMA issue. Who knows how much money end users lost from downtime, because someone somewhere between us and the end user, decided to rip them off.
Software folks don't care. The last thing they do, both free and proprietary vendors, before releasing software is attach language like this:
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
or this
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
So who cares if their IP is ripped off?
My former employer can't do that. People may die if our products fail. There are statutory requirements to comply with. So we charged a lot for our products and offered iron-clad, no-exceptions, on-site support.
Instead of engineering down to a price point, we engineered for maximum safety and reliability.
But Wang Da Nian somewhere in Shenzhen decided that ripping off our designs, firmware, and trademarks and using the shittiest parts possible to insure that it would operate when installed all while taking the time to make it look EXACTLY like our product was a good business decision.
That hardly sounds like a success story for the current copyright/patent regime. Given that you had to resort to technical measures anyway, it sounds like the law was entirely useless to you. Meanwhile, we're all still paying the costs of it.
It seems obvious that IP provides some incentive to create, although how much is completely unknown. It also seems obvious that even in a world with no legal protection, people would still want to create, though again, how much is unknowable.