> Why should we subject ourselves to it?
The traditional reason is to grant incentive for its creation in the first place. One primary example has been medical advances. With the benefit of a (temporary) monopoly on the sales of a new drug, the company has an incentive to create it in the first place. Perhaps we wouldn't have as many life saving advances without IP protection. A secondary reason is that it requires public disclosure. One alternative to patent protection is to keep a production method a trade secret. So companies, if they are sufficiently secretive, could have effective if not legally enforced monopolies due to such secrets. So is it worth the tradeoff of having IP protection?
COST: a time-limited monopoly; limited incremental innovation on derivatives of the protected work during the lifetime of the protection.
BENEFIT: potentially more innovative goods and services are created to begin with; the means and methods behind these innovations are publicly documented for future replication or derivative work .
I'm think it is worth the tradeoff both for copyright protection and patents in general. But the specific laws are certainly not optimal as currently written and enforced by the courts. Durations for both patents and copyright are too long. Plenty of things that are patentable should not be, due to them being too obvious, trivial, or just not appropriate for protection.
Also the remedy for infringement has multiple options. You could allow general infringement, at statutory royalty rates. I think Canada has experimented with this for copyright, and the US as standard (but private) arrangements for the licensing of music. You could require a fraction of any profits. These provide the monopoly rents, but not a monopolization of production and derivatives. We are still learning what the optimal tradeoffs are for society. I hope we have more experimentation on regulatory regimes to identify the best compromises.