The fact that IP protection is expensive is essentially its defining
feature. One way to think of "intellectual property" is precisely as a weird proof-of-work, since you are trying to simulate the features of
physical property for abstract entities that by default behave in the exact opposite fashion.
This is the frustrating thing about getting into an argument about how "IP isn't real property" and then having the other side roll their eyes at you like you are some naive ideologue. They're missing the point of what it means for IP to not be "real property". The actual point is understanding that you are, and will be, swimming against the current of the fundamentals of these technologies forever. It is very very difficult to make a digital book or movie that can't be copied. So difficult in fact, that it we've had to keep pushing the problem lower and lower into the system, with DRM protections at the hardware level. This is essentially expensive, not just from a capital perspective, but from a "focus and complexity" burden perspective as well. Then realize that even after putting this entire system in place, an entire trade block could arbitrarily decide to stop enforcing copyright, AKA, stop fueling the expensive apparatus that is is holding up the "physical property" facade for "intellectual property". This was actually being floated as a retaliation tactic during the peak of the tariff dispute with Canada[1]. And in fact we don't even need to go that far, it has of course always been the case that patents vary in practical enforceability country to country, and copyrights (despite an attempt to unify the rules globally) are also different country to country (the earliest TinTin is public domain in the US but not in the EU).
Usually at this point someone says "It's expensive to defend physical property too! See what happens if another country takes your cruise liner". But that's precisely the point, the difficulty scales with the item. I don't regularly have my chairs sitting in Russia for them to be nationalized. The entities that have large physical footprints are also the ones most likely to have the resources defend that property. This is simply not the case with "intellectual property," which has zero natural friction in spreading across the world, and certainly doesn't correlate with the "owner's" ability to "defend" it. This is due to the fundamental contradiction that "intellectual property" tries to establish: it wants all the the zero unit-cost and distribution benefits of "ethereal goods," with all the asset-like benefits of physical goods. It wants it both ways.
Notice that all the details always get brushed away, we assume we have great patent clerks making sure only "novel inventions" get awarded patents. It assumes that patent clerks are even capable of understanding the patent in question (they're not, the vast majority are new grads [2]). We assume the copyright office is property staffed (it isn't [3]) We assume the intricacies of abstract items like "APIs" can be property understood by both judge and jury in order to reach the right verdict in the theoretically obvious cases (also turns out that most people are not familiar with these concepts).
How could this not be expensive? You essentially need to create "property lore" in every case that is tried. Any wish for the system to be faster would necessarily also mean less correct verdicts. There's no magic "intellectual property dude" that could resolve all this stuff. Copyright law says that math can't be copyrighted, yet we can copyright code. Patent law says life can't be patented, yet our system plainly allows copyrighting bacteria. Why? Because a lawyer held of a tube of clear liquid and said "does this seem like life to you?" The landmark Supreme Court case was decided 5-4 [4], and all of a sudden a thing that should obviously not be copyrightable by anyone that understands the science was decided it was. There's no "hidden true rules" that if just followed, would make this system efficient. It is, by design, a system that makes things up as it goes along.
As mentioned in other comments, at best you could just flip burden to the other party, which doesn't make the system less expensive, it just shifts the default party that has to initially burden the cost. Arguably this is basically what we have with patents. Patents are incredibly "inventor friendly". You can get your perpetual motion machine patented easy-peasy. In fact, there is so much "respect" for "ideas" as "real things", that you can patent things you never made and have no intention of making. You can then sue companies that actually make the thing you "described first". Every case is a new baby being presented to King Solomon to cut in half.
In other words, an inexpensive system would at minimum require universal understanding and agreement on supremely intricate technical details of every field it aims to serve, which isn't just implausible, it is arguably impossible by definition since the whole point of intellectual property is to cover the newest developments in the field.
1. https://www.cigionline.org/articles/canada-can-fight-us-tari...
2. https://tolmasky.com/2012/08/29/patents-and-juries/
3. https://www.wired.com/story/us-copyright-office-chaos-doge/
4. https://supreme.justia.com/cases/federal/us/447/303/