It is a complex issue, no question, but you also have to look at the different perspectives involved, and then go into each one, because there are a TON of differences between different areas where copyright comes into play.
For music, the system is so broken that it isn't funny, mostly because the "artist" generally sees far less than the record labels. Yes, there is the cost of the recording studio, staffing, and all that, but once that expense has been covered, the cost of duplication has gotten so low, it is almost criminal that the record labels get such a large percentage of the revenues. This is where people feel more "justified" in downloading music "illegally", because the artist probably would never see any revenues from a legal purchase anyway.
For books, it becomes a bit more difficult, because to write in the first place, with the goal being to make a living from it, is a VERY risky thing. If an author writes one book that is popular, how much of the revenues go to the author, but then again, if a book is popular for the life of the author, and people buy it, shouldn't the author make money on each copy? The idea that one person buys a book(which takes months, if not years to write) and then would COPY it, while keeping the original, when the proceeds MUST be enough to cover writing the next book is where authors do deserve some protection. If the demand to read the book is so great that a COPY is made for a friend or relative(rather than transferring the existing book to the other person), then the author does deserve some compensation for writing it in the first place, since the book will still be in print.
For movies, the cost of making a movie is huge, and the number of people involved is large enough where the movie studios NEED extra income just to make sure they can stay in business if one or more movies in a year do not sell very well. If you figure $200 million as the cost to make many movies is there, then what if a movie is a flop, but YOU like it. The more money the studio brings in from that movie, the less of a loss there will be, and it will encourage more movies overall, even if there will be some bad ones in the mix.
Then you have software. If you work for a company and you get a paycheck for your work, then you have a certain amount of security, and probably benefits(health and such). Software publishers COULD make money on software written 15 years earlier if it is kept up to date. The key here is that a BUSINESS that exists to produce software needs to bring in enough money for MULTIPLE software releases. 3-5 years per program, so, how much money does the developer need to bring in from the sale of each program to make the business profitable? Yes, there are examples of some wildly successful software companies out there, but most live, produce a few titles, then die off, and THAT is where the problems come from.
The basic idea is that if someone can duplicate the effort of others and produce something similar, then that should be allowed(so music artists who cover songs from other artists), but if you can't write programs yourself, then you should not be allowed to just copy the work of others and claim you don't agree with copyright. Those who don't have the talent to independently reproduce the work of others is the problem here.
There really are two aspects here, the cost and effort to reproduce the work in question, and then the cost to be the author of the work in question. In the days when you needed a printing press to reproduce a printed work, then the effort required was LARGE, and on top of that, if the author was compensated for the composition, then there should be no problem with multiple publishing houses releasing the same book.
Software developers should in theory have the same option, where multiple publishers could be used, and the one that best sells the product makes the most money. The developers then are still the ones who profit on the software itself, and those who package and sell the product can make money on that side of it(so a program might cost $20, and the package, shipping, and so on might add $40 to that price, or $20 extra for the electronic version. Advertising and such could be the thing that draws consumers to one publisher or the other.