Yes and No. The 1st gen owners have enjoyed their iPad Pro's for a year and now get the chance to have all the latest refinements / tech (and extra storage). And they can sell the 1st gen to offset the price of the new Pro having gained a years usage out of it as a main computer. There is a chance 2nd gen owners won't upgrade next year.
But that's always the case for every new generation. No matter how little they change. You can always sell and upgrade.