In my opinion, anybody who thinks 'Satoshi' didn't create Bitcoin with the intention (at least, in part) of getting rich, I think you're fooling yourself. It's clearly built into the structure.
Yet we haven't witnessed an intense development effort for such novel systems before or since Bitcoin. There were many different plans for a distributed currency (e.g. a distributed anonymous version of ripple), but only by a handful of people. In my experience, you just can't and don't work on such stuff if you intend to get rich. He must have imagined gaining wealth as a consequence of his success, but the reason the structure is built this way is definitely about success of the currency. As a consequence, people who believed in it got to have more coins. Even so, there are many early adopters who (at least claim to) have very little coins left.
To me, this is a a weak argument. Obviously, we haven't witnessed an "intense development effort for such novel systems" since Bitcoin because that would be a period of what...2 years? And, the Internet has only been around for a
couple decades before Bitcoin. The age of digital global information exchange is still in its infancy. And, I would argue there have been novel attempts on a smaller systemic scale. Linden dollars, for one. Did Linden dollars make the 2nd life owners wealthy? You betcha. Now you got Facebook Credits. Perhaps you could even go before digital communication and look at things like Baseball Cards, the popularity of which exploded in the late 1980s and early 1990s. This could be thought of as a currency for kids (after all, there were price guides that pegged the value of a baseball card to a fiat currency). Who got rich? Baseball card manufacturers (the Satoshis) and card shops (the exchanges).
Edit: With the baseball card analogy, although they were also very popular back in the days when kids put them in the spokes of their bicycle wheels and milk men delivered them at your door, the explosion of popularity in the late 80's and early 90's was aided through digital communication. Online price guides, auctions, etc. helped to 'stabilize' the value of cards.