You have a lot of opinions, and they are just that: opinion. I would like to see some numbers to support your claim that "if copyright violation was legal, a Steam-like system would spring up in 2-3 months".
As I see it, we have 3 groups involved in copyright violation. Assuming we are talking about a movie, these would be:
1) Die hard fans who insist on going to the movie theater and owning an official copy of the DVD once it comes out.
2) Normal people. Some will see the movie, some won't have time, some will buy the DVD, some won't have the money.
3) Die hard pirates. These will never pay for the movie, out of principle.
Of these, group 1 will never pirate the movie, so we can ignore them. Group 3 will never pay for the movie, so there are no lost sales, so we can ignore them too. Out of the largest group, group 2, a significant proportion may pirate movie. But why? They may not have money, or consider the price of the movie or DVD excessive. This sub-group, then, are not the target market, so there are no lost sales. Some may have no time, and thus we can also exclude this sub-group, because they would never have time, regardless of the legality of copyright violation, and thus no lost sales. So what is the situation we find ourselves in? The target market of movies and DVDs - those with the funds and the time to spend - will likely purchase the entertainment. Those outside of the target group - those who cannot afford it - may pirate the work so that they can also enjoy it, but even if piracy was impossible, they would simply not purchase the work, no lost sales, no harm done.
What can the movie (and by extension, the entire entertainment industry) do about this? In my humble, non-professional, armchair-critical opinion, they should stop worrying about those who are not their customers (people outside the target market, just as the fashion industry is doing) and/or change their business model to make them their customers once again. Raising prices will do nothing, it will only make the second group larger than before. Legally persecuting pirates will not help, as it still will not make those unable/unwilling to purchase their material change their minds nor their situation. What they can do, however, is provide services that directly compete with piracy. If Prada wanted to combat copies of their items, they could lower their prices so that purchasing an official copy becomes worth the price to a larger group of people. Similarly, if the entertainment industry wants people to stop pirating their works, provide a viable alternative, or stop complaining.
You talk about Steam-like systems. Then lets look at Steam itself. It is incredibly successful, and offers many low-cost games, specials and weekend demos to entice more customers to pay. Not only that, but it provides a common, easy to use, system for purchasing, and downloading new games. It is a viable alternative to piracy. Yes, piracy still happens, and it always will. Even if you entice all of group 2 to become your paying customers, there will always be group 3 who refuse to pay, not matter how little you charge. Similarly, there will always be people who will only buy knock-off fashion items, and will never buy and authentic piece. There will always be people who obtain all their music from recording songs from the radio, or copying CDs from their friends. There will always be people who wait until movies come out of TV, or borrow their friend's DVDs and copy them. These people will never go away, and it's pointless to try and make them. Instead, the entertainment industry, like the fashion industry, should innovate, and make a valuable, viable, alternative to entice as many people from group 2 to pay for their products.