The only reason they aren't putting nike plus on 1st gen is so people will want to buy the 2nd gen- this is wrong and yea they can do whatever they want but wake up already.
This is an assumption that you have stated as fact. I work in mobile devices for the military, and ensuring you've built in forward compatibility with every possible accessory that will be built is very, very hard. Doing this while keeping the cost cheap is next to impossible. You could argue that since the Nike+ system predated the iPod Touch then the touch development team should have anticipated and built in the ability to use the Nike+ accessory in the first place and that argument has some merit. I don't know how much it would have added to the cost of a 1g iPod Touch to include compatibility to the Nike+ system but Apple has hobbled devices in the past for marketing reasons rather than financial or technical reasons (e.g. to differentiate between different models). I find that a distasteful practice in general, but it does make for a very clear and understandable product line. I could be an armchar product designer and argue about what they should or should not have added to each of their devices till I'm blue in the face, but Apple seems to be doing a pretty good job for themselves.
But since they did not make the iPod Touch compatible with Nike+ in the first place, that leaves two options:
1 Build a specialized Nike+ connector designed exclusively for the 1st gen iPod Touch. Not only is Apple not in the habit of building accessories for discontinued models, it could be very hard to make an adapter that would provide the same interaction and UI that have been built-in to the 2g iPod Touch.
2 Build new capabilities into new devices, and back-port them to old devices only when you can do it for free/cheap.
All these metaphors about cars and whatnot are misleading at best. It's a few hundred bucks for a consumer electronics device. If you want more capabilities than you originally paid for you might get them for free. (Yay!) Or you might have to upgrade. But claiming that apple forces you to upgrade to get new capabilities purely out of malice or greed betrays a seriously naive view of consumer electronics. They need to make a profit and please most of their customers in order to stay in business. I hate to burst your self-important bubble but the sheer cost it would require to satisfy a few cranky forum posters is probably not worth it in the long run. Apple is realistic, not malicious.