Statements like this just feel wrong to me. Shouldn't there be some difference between being a monopoly and simply being successful?

Google isn't doing anything to stop you from building a competing search engine, and people try every so often (Cuil, Wolfram Alpha, etc.)

Also, Adwords are sold at auction, so doesn't the market set the price? The only sketchy thing I've seen with Adwords is that you're able to purchase someone else's trademark as an Adword.