I think a very large part of the problem, is that our society has somehow come to the conclusion that yes, they can be. I strongly disagree. I think a better way to look at IP, is as an "intellectual lease".
When you have an idea, as the person or group who originally conceived of it, you are presumably in the best position to make use of it. You can therefore "lease" from society, the right to use it exclusively for a short, well defined period of time. At the end of that term, your lease expires.
At no point do you "own" the idea, because as soon as you release it into the world, it is already in the minds of many, some of which may be able to put it to better use than you, or to improve it faster than you.
This has several ramifications, including ones that effect creative works too. I posted a few long comments recently about copyright that expresses my view, but to summarise - creative works should have a limited window during which the author or creator can be the exclusive seller of the work (eg copyright should be about restricting who can profit, rather than who can copy). After that time, anybody is free to sell as well. This has many benefits. I used Harry Potter as the example last time as it is well know. Harry Potter now is known by almost everybody. We all know the story, we know the characters. JK has made a ton of money - more money imo, than any one author deserves, but that aside. HP is part of our collective humans story now. If I want to make a mobile game about it, or write a play about it, or adapt it for a new medium, or translate it - why should I still owe the original author royalties when I could reproduce the plot from memory? Again, I use the example of ancient Greece, and the way in which aural story telling was paranount. Stories spread, adapted, becamr part of society. The ones that survived that we have written down are simply one version that would have been told aurally at one point in time. The way that we insist that works and derivative works be set in stone in order to maintain profit is prioritising profit over the joy that is the spreading and adapting of stories that has been central to most human cultures since the beginning.