What it does is reduce the profit of those corporations, which may make their business unsustainable and lead to this market shrinking, which may cause economic instability while people reorganize their effort towards another market. Those are all hypotheticals though, because the industries affected by piracy are all growing fairly rapidly.
Does competition weaken the economy? There's plenty of examples(e.g. computer hardware) where competition has eroded profit and changed the market dynamics, especially for new entrants. Do clearance sales weaken the economy? Free samples? Does generic medicine hurt the economy? There's so many cases of corporations not realizing the profits they might have wanted, but I don't see how they weaken the economy.
Not everyone can afford to have fun and that's ok. Some people's place in life is to be workers.
Do you have any suggestions on the prefered skin color or ethnicity of the people who need to be workers ?
As for people affording to have fun, my experience is that the working class aren't using entertainment to have fun, so much as they're using it to dull the pain and tedium of a fairly shitty existence.
I tend to agree that one should tend to work to improve one's life, but never forget that actively finding content to watch is work. And having access to a large library of digital media is something no amount of money could afford 100 years ago. And lets not forget how cheap super computers are that even homeless people tend to have one in their pocket. So, yeah econonic position matters, I guess.
Also, piracy is, most of the time, a master of convenience: Netflix/Steam have reduced pirating way more than any anti-P2P law.