It must have been many years since you were in Vegas because these conditions have deteriorated for a long time. I think the last decade has been the worst. The consolidation in the industry has meant less choice and less competition. Assigned seats for tickets has been around now for over 20 years in the major rooms. That is not necessarily a bad thing. I liked assigned seating. If you want better tickets, pay the show more, rather than bribe an employee who is using his position to enrich himself. It is the same reason the hotels are now aggressive in selling upgraded rooms which used to be reserved for gamblers. Because rather than have the check in clerk get the money, they can get the money.
Now that you mentioned Penn and Teller, I should have mentioned this - f you have a Caesars Total Reward Card (which is also the old Harrah's corp) you can get free tickets for Penn and Teller, Mac King and some others less prominent shows if you have Diamond Status. Buy one get one free (BOGO) if status is Platinum. You can do this once a month