Ooh, I love this analogy - see, some users DO get the new firmware for free. Can you imagine the uproar if Apple had given Leopard for free to MacBook Pro owners, but made MacBook owners pay?
People who buy new iPod touches will get 2.0 free, just as people who bought theirs after 1.1.3 was released got it free and those who bought Macs after Leopard was released got that free. I fall into both of those categories.
If you bought your touch before 1.1.3 was released, then you bought a music player that also had safari and email wifi. If you bought it afterwards, you bought a music player that could double as a PDA. If someone who bought the original music player wanted PDA technology added to their device, they had to pay for it, plain and simple. That will apply to 2.0, as well.