Disney's a business, and they have found ways to monetize things they used to supply for free. It is what it is.
Guess again. If your expedient entry enables you to enjoy twice as many attractions as I was able to because I was waiting in line behind you, that impinges on the value I receive from the same entry fee we both paid -- with your time-stealer supplement being the enabling difference.
Let's say we both pay $300 to fly from Baltimore to Orlando. You pay $100 per year for expedited security clearance. That means (if that's the only flight you took that year, unlikely) you paid $400 to get to Orlando, while I still only paid $300. But our plane left the gate on time and we both got to Orlando at the same time. No diminished value for either one of us -- you're happy that you got to sit with a drink for 20 minutes while I was waiting for the TSA lady to give me a little tickle and I'm happy I got on my flight to WDW.
Now let's say we each pay $250 to get into the MK for 12 hours. You pay the $30 Genie plus fee and I don't. We each have a minimum expectation of experiencing 8 attractions. But because you paid extra and are able to shorten your wait times considerably, you get to experience 12 attractions while I only get to experience 6 because you paid to get ahead of me and skip the stand-by lines. That's diminished value for me and enhanced value for you since you paid for expedited entry to the attractions at the expense of my time (and that of everyone else you bypassed in the Genie+/ILL line). Limited time in a theme park has value -- you recognize that since you paid extra for shorter lines, with the ultimate effect of making us wait longer. Hence, our time was stolen by Disney and sold to you.