iMO, the decline started when Binion's Horseshoe closed the first time. Once the casino was bought out and the place renovated, it lost that old timey western saloon charm I always enjoyed. During the bankruptcy, they sold the million dollar display that had been there for decades. Before they sold it, taking your own pictures in front of the display was encouraged. Then they posted signs that only photos taken by staff -- for a fee -- was allowed.
i remember walking into the main blackjack area on the Fremont side, and it was .... quiet. looking around, I saw that the slots around that long pit area were turned off. A supervisor explained that the casino has to have enough cash on hand to pay out a jackpot on every game, or it can't operate them. About half the machines throughout the casino had to be turned off.
Once the place reopened with scantily clad women in cowboy attire, bright lights throughout the place, and noise to rival the busiest Station casino, I stopped going back. Went from being by favorite downtown casino to bottom of the list.
That's about when i noticed downtown as a whole began changing. Maybe it was a signal for them to catch up with the times .... that it's not the 1930s anymore?
The next red flag that old Vegas was dying was the restaurants. Binion's has a prime rib and steak special that couldn't be beat. They closed that restaurant and went to buffet exclusively. The food quality sucked. Fremont had a $6 breakfast special -- 2 eggs, pancakes, bacon, sausage, ham and coffee. That went away, too.
Everything has been in a slow decline for years before the pandemic. That's why there are new casinos downtown now. Lots of developers and owners lost lots of money in the Obama years starting with the housing crash. People didn't have the funds to visit (lose), and with low interest rates artificalliy kept low, business borrowed and borrowed to invest. Many of those properties changed hands when they couldn't repay the debt due to low attendance.
So, after a decade and a half of difficulties, the pandemic hit. I remember when the Cal hired extra staff to clean each machine after every use when the Norwalk Virus was rampant. I can't imagine the cost of keeping a casino clean with a more deadly virus. Many are still afraid of leaving their homes no matter how much the casinos try to clean.
Then came the parking. It used to be a well-known secret that you could park for free at almost all casinos if you just tipped for valet parking. Most self-parked thinking valet would charge for parking. With the additional cost of self parking, i imagince more are using ride shares. Why spend that money for your car to sit when you can spend it on rides? Drink all you want -- we're taking an Uber!

Following that came the "resort fees." A scam if ever there was one.
Vegas has always catered to the average person by trying to make them feel special so they will feel more free to blow the money they saved on games. Now, it's a totally new landscape. With online gaming and casinos in many states' back yards, there's a lot of competition for the gamblers' dollars. Vegas now caters to the event crowds. Check out a calendar for Vegas events. It's packed. And now Formula 1 racing will be returning in 2024.
They know conventions and sports events mean lots of people coming just for those things. Enticing them to come is not needed -- they've already decided to be there for the race, the sports event, the convention, the rodeo, etc. So, the new Vegas is designed to "sheer the sheep" as quickly and as cheaply as they can. Hence the high table limits. From what I've read and seen of videos, the machines are also less "loose" now.
Biden didn't help matters with his high inflation partially caused by all that stimulus money during COVID.
Vegas used to be in the fantasy business -- an adult Disney Land. Now it's a typical tourist trap with higher prices and less value.
I only see it getting worse.