I have virtually no first hand experience with big stadia or their decay. But I understood that the owners want new arenas built in large part because the trend is for lots of huge private suites that high rollers can use. An in-house convention facility is good too. Along with an all weather surface and retractable roof. This just wasn't part of the typical design 30 yr ago.
Hell, they tear down shopping malls that are less than 30 years old. Just did it down the road from my house last year. It wasn't because the roof was falling in (it wasn't); it was because you can't make a profit with a building like that. Revenue in our society means having all the latest bells and whistles. If it ain't multi-story, dramatic atrium and skylighted, with mega-cineplex and huge food court, then it's not worth shopping at. I mean, the jeans fit SO much better when I have to walk past the food court and mega-cineplex to buy them. Right?