Because those companies have enormous teams of lawyers and divisions that spend their entire lives doing nothing but suing and issuing "cease and desist orders." And those tech companies do write software that is much much harder to encypt and decode. There are companies that are devoted to all of that, yet China still steals intellectual property.

Generally, for lawsuits, something has to represent actual MONEY to be sued for. That is why the only copyright lawsuits you find are when one major writer sues another major writer, People are actually hearing and seeing those songs. Where as most will never be heard by anyone outside of close friends and family. So there is no money to speak of. But sometimes even the biggest artists have their material taken.

A few years ago, a rapper named "Frank Ocean" sampeled the music tracks of HOTEL CALIFORNIA, and inserted his rap lyrics over that and offered it as his own. Not the general chords, not a small section of the song, but the ENTIRE MUSIC TRACKS of the intro to HOTEL CALIFORNIA. He just took it all. When someone pointed it to Henly and Frey, and they wrote a very polite letter informing him that while they appreciated new artists, and the desire to create their own works, it was quite illegal to do what he had done.
The rapper basically told them to shove it. This was followed by several months of not so nice letters from their manager Irv Azoff, attorneys, etc. All while Ocean continued to make his reputation and sell hundreds of thousands of copies and downloads on his "song." Finally, it was stopped, but he had moved on to become a star in the rap world.

So yes, there are too many songs. But basically if it is "out there", it is difficult if not impossible to do a whole lot about it.

MAB