Evidence of Patent Infringement?

So American Pharmaceuticals are thinking about barring other countries, like Thailand, from manufacturing generic drugs.

Is there proof that these practices hurt the American pharmaceuticals, if its all the way in Thailand where these drugs are processed and sold?

How is this solution practical? Why? I just don't see it. What possible other advantages could these companies have. The people who buy generic medicine for diseases like AIDS or whatever, they can't afford American drugs anyway. So what's the deal?

One argument I've heard is that, legally, if you fail to protect your patent or trademark in some cases, you can lose the ability to enforce it in others.

But to just an ordinary observer, it looks like pure greed.

There argument makes economic sense, because if people in other countries have access to generic drugs, they will not buy the drugs from the company that invented them (and had to pay for all the cost of research and development). R&D is by far the most expensive component of the process. If people (in other countries or here) buy generic drugs, they aren't paying for the research, meaning that Americans have to pay for it. So basically, American consumers are subsidizing drugs for other countries by paying the entire research and development costs, while people in other countries are only paying for the manufacturing.
Your idea that people in other countries can't afford American drugs isn't exactly right. There is no reason that American companies have to charge them the same amount they charge here. But of course, if the government doesn't enforce patents, then the company that developed the drug can't compete with generics that didn't have those expenses.