While Disney ticket costs may make it seem like it's a higher price point, it's actually a more affordable trip than many of the other popular destinations. In the case of Yellowstone, park entry may be cheap in comparison, but the cost of getting there and having transportation while there more than makes up that cost difference...unless you're willing to burn an excessive amount of vacation days on an extra long road trip...which most people are not going to do. i.e. 5-6+ road days is too wasteful. Air options are also limited into this part of the country and typically priced 2-4x higher than anything I've had into MCO. In fact, the harder it is to get someplace, the more entitled people seem to feel as well. And the majority of the lodging inside the park is on par with the pricing of Disney mod to deluxe resorts, so there's certainly no lodging savings unless you've wrangled one of the rustic more economical options. In general, lodging in the park is significantly more difficult to secure than anything involving a Disney park...even during peak times. And while there are a few access points that have lodging that might be easier to book, staying offsite at a place like Yellowstone isn't nearly as convenient or cheap as staying offsite for a Disney park. And while dining options aren't as plentiful, the main hotel dining rooms require reservations, advanced booking preferences are extended to guests of those specific hotels, and since it's not a place you generally want to be driving after dark, demand at home resorts is high. So, lots of "I paid this much" and "I had to work this hard to get this for us" at play.
Alternately, let's look at ski trips. A good number of ski resorts have major airports that are close enough that you won't be paying Yellowstone kind of prices for air, but many people are looking for ski in/ski out and don't want to have to drive on winding icy mountain roads. So, they pay heavy price tags for airport shuttles to and from resorts, and upper end deluxe pricing for ski in/ski out convenience. Daily lift tickets and gear rentals often eclipse Disney gate ticket prices and unlike Disney, which goes into the nighttime hours, your ski day is often done between 4-5pm.
The point I'm making is that in a Disney focused group, people often assume that Disney is this in this ultra high price point above other popular trips, when that's really not the case. Yellowstone usually costs us a couple thousand more than a nice onsite stay at Disney...and that's with cutting a lot of corners for YNP. In 2015, we blended ski time and
Disneyland time and our ski days cost more than double what any of our Disney days cost...and that too was without any real splurging. I'm by no means suggesting that Disney is a bargain basement trip, but after planning enough trips and seeing all of the ways you can save, I don't consider Disney to be in this higher price point than other top vacation spots.
Obviously, there are crowds in the Disney parks, but any popular spot will have crowds. Old Faithful's crowds in peak season can rival the feeling of waiting for fireworks in a Disney park at peak. And while you won't be walking around in most parts of YNP and feeling the crowds like you would at Disney, you will be sharing the road with them since many people choose to drive around the grand loop to look for wildlife and scenic vistas. So, imagine all of the hate people have for the so-called rude guests who stop dead in their tracks in the middle of MSUSA or "drive" erratically with their strollers...and put them behind the wheel of a car behaving the same way while touring YNP. Or if you want to use a skiing example...at Disney, we always hear about lines...but if you're skiing at a peak time or a weekend, you'll likely spend 70-80% of your day in lines waiting to get up on the lifts. You'll certainly encounter a lot of bad behavior when people have to do that much waiting. So, your crowd challenges might not be mirror images to Disney's, but the entitlement blended with the crowd frustrations can breed equally frustrating rude behavior.