I was also surprised by this approach at Alibre. It's new to my experience with software licensing too. I did express a similar opinion to the last couple of replies here in another thread some time back, but it's worth repeating.
There are also distinct advantages to having the top-of-the-line version, Expert, contain ALL the current goodies. Besides the obvious homogeneity for support purposes, it vastly increases the perceived value of the product to professional users and creates product loyalty and gives Alibre an expert-class of users to hammer away on new features or products and to "spread the gospel" so to speak with respect to the usefulness and value of Alibre Design and keeping it current through maintenance. This seems truly obvious to me. Apparently, many other software companies see it the same way since that's what they do with their top-end products.
It might mean slight increases in maintenance fees over time to accommodate the additional functionality added, but you don't have to do it by recovering 100% of the cost for your new addition or functionality in round one from your existing high-end users. You spread the costs over time and may charge new purchasers of Alibre Design Expert slightly more for their initial purchase of the software and slightly more for maintenance, but not more than existing users - charge all the same amount for maintenance.