This is a good point and is one of a large number of challenges BTC faces. Right now, a small transaction fee ensures that your transaction will be processed q

This is a good point and is one of a large number of challenges BTC faces. Right now, a small transaction fee ensures that your transaction will be processed quickly. This distributes the cost of validating the transaction. Eventually, we may see the transaction fee structure become less of an option and more of a necessity. BitcoinJ (the Google 20% time project) uses a very compressed and less comprehensive block chain to make transactions but is not intended to be used to generate coins. In other words, the problem is being mitigated. The level of innovation in the BTC community is jaw dropping.