The number of people who spend money on things like Express passes is negligible compared to the number of people who don't. Even with them being sold, Forbidden Journey's standby queue - to keep using that example - still gets packed. Jurassic World's still gets packed. The Studio Tour still gets packed. If we take Express passes out of the equation, hypothetically get rid of FJ's queue or MK's queue, and let thousands of people on any given day who've come primarily for one of the headliner people eater rides like FJ or MK loose with no place to hold them anymore, I think the congestion problem still remains the same. If standby queues weren't a thing for major rides, then the whole park would just be people shoulder to shoulder milling about waiting for their times to come up for any given ride or clogging up stores and so forth.
...which is exactly why MK's long standby line is important? It's going to be a madhouse as it is already; now imagine no standby line having been built at all (which was the original statement made, not whether MK will or won't have a VQ) with hundreds, even thousands, of people all crammed in with nowhere to wait. I seriously doubt the creative team was just like, "Hey, let's build a long queue for no reason." They know what they're doing and why when it comes to something like this.
Either way, if you guys completely disagree with me, it's totally fine. I'm not gonna go back and forth on this point anymore when I feel like I've said all I can say towards it. No point getting into it over... queue lines, of all things, haha.