You are so wrong. Let’s use your logic and see how it applies.
Nokia has added new features to existing phones. They are not new products; Nokia has sold for a number of years. It’s just that they allow current owners to update to the same firmware that new phones will ship with.
Nintendo has provided updates to its products and they have been making consoles and handhelds for years. Once again, not a new product.
The PSP is new to Sony, but a console is not and Sony continues to add new features to the PS3 through updates.
The above have all been free. How can they do it and not Apple?
Also, Apple has provided free updates that added new features to the iPod in the past. Do a search and find them!
Nokia, Sony and Nintendo are all publicly traded companies, just like Apple. Ever think that Apple is using the interpretation of SOX as an excuse to charge?
Also, using your thinking, wouldn’t Apple need to charge an extra $20 for a new iPod Touch to cover the new software? Of course not, the R&D will be paid for by new sales. You just don’t write it once and never update it.