Why do people continue to pay such absurd concession prices and ticket for and at concerts and professional sports games?

Another answer. How are they going to pay all of those multi-million dollar yearly player salaries if the don't steal it from the fans.

cause they think its worth it

I don't go to sports games, but I've been to a fair amount of concerts as of late. How the money gets broken up varies based on the venue and agreement, but suffice it to say, the bulk of the ticket price goes to the expense of having the performer. That's not just the cost for the lead musician and the band, but also for all the other things that go along with production, like lighting, sound, insurance, etc. Smaller venues often don't get a cut of tickets, or if they do get some, it's very small. That's because the performer usually has to bring in his/ her own crew. When you get into larger venues, they do have their own crews, and so they usually command a higher portion of the ticket price. 

So, then it comes down to how the venues can afford to exist if they're not getting a big cut of the ticket or not getting a cut at all. Food and drinks are the obvious ones. They may also charge for things like parking. I know if I go to a little dive club, their drink prices won't be insane, but the more amenities offered, the greater the security presence, and so on, the more expensive the drinks will be. Out of all the venues I regularly go to, the one with the biggest security force is the one with the most expensive drinks. Actually, that's a pretty good indicator overall. Those with a bouncer or two at the door tend to have more reasonable prices. Those that make me go through a metal detector or use a wand prior to entry charge more. 

Some venues get sponsors as well. That helps them keep their overhead costs lower, but at the end of the day, the venues have to find ways to make more money on their own, since they're getting very little from the tickets.

Whether or not I'm willing to pay the high prices depends on a number of things. I know the prices of most of my local venues. I plan ahead before going to one of the more expensive ones and don't buy anything there. I sometimes park further away or take a Lyft, so I can skip the parking fee. There are times I budget for a couple of drinks. Here, it's a million degrees out. If we're putting hundreds of people in a small room on top of that, you're going to need something, even if it is a $4-5 bottle of water. One venue a couple weeks ago charged me $4 for a $1 bottle of Gatorade. lol It's part of the cost of going out, and so I may not even buy a ticket if I can't afford some kind of beverage. When I do pay, though, I minimize expenses and budget ahead. I don't like the fees, but I also recognize where that money is usually going. Particularly when I can see my money has gone to support a local business or there are features like robust security, I feel better about it. 

Used to be, my family would go to the county or state fair as a big trip.
We would avoid the (rip off) games ... but enjoy the rides and exhibits, and the food wasn't too expensive.

Now, there are hardly any exhibits ... the rides are full of obnoxious teenagers ... and the food is far overpriced for "grease on a stick".

Thank goodness the classic car shows still allow you to bring in a "picnic" lunch.