Let me address a few misconceptions people often have:
(1) Apple doesn't arbitrarily decide on their profit margins. They price their products in a way to ensure their competitive status in the market over the short- and long-terms. If adding something to the iPad changes these margins (or changes the price of the iPad) in a way that is detrimental to the company's long-term success, then they won't do it. Why? Because they aren't colossal idiots who want to wreck a company.
(2) Apple doesn't just build the 'super-duper iPad' and then remove items from it right before they ship it to consumers. Tooling costs, sourcing components, and so forth can't be changed on a whim.
(3) Apple doesn't make you buy anything. All technology improves. If you bought the iPad when it came out and also buy the next iteration, that's your business.
(4) If Apple 'put all the technology they could' into the current iPad then the next iteration wouldn't be around for another several years. You can't have it both ways.
Actually, points 1-4 are total nonsense. The iPod touch could have been released in 2002 but Apple just held things back to gouge people out of their money.