I think what many people who say "don't base your business on Google", "Google doesn't have to give you free traffic", etc. miss is that search is the way a great many people find products to buy, businesses to frequent, and information they're interested in or need. That's how it is in 2011. When Google makes a massive change and your site is no longer visible to users, it's exactly the same as if you had a physical store and you wake up one morning and your store is no longer on the street it used to be on. Instead, it's in some housing project or flooded and under water.
I started working online when my former business was wiped out by Hurricane Katrina. When I got hit by Panda on 2/24 it felt as bad as Katrina for my way of life, minus the destroyed city, etc. It really can be that bad.
In 2011, the Google SERPs are like a shopping street for a physical store. No city or politician lightly decides to tear down buildings or remove access to a street and screw all the existing businesses. If you have an online business that you depend on for revenue (and some of those businesses have an offline component as big or bigger than a physical outlet, with employees, a warehouse, insurance, fixed expenses, etc.), you often must be found in the organic results. Is it wrong to expect that to be the case? Of course not. It should be. And if Google was the slightest bit "moral" they wouldn't torch thousands of businesses without giving them PRIOR guidance on what needed to be done to avoid getting your life, your business, and your employee's lives totally F#^%#%.
Google is doing experiments with people's lives in a way that would absolutely not be tolerated in the physical world, and very few people are calling them on that.