I didn’t see it but I’m guessing these ‘experts’ are just academics i.e. they know a lot about something they’ve never actually done.
What they’re trying to get across, which I very much agree with, is that a promoted club shouldn’t be carrying a wage bill much more than £40m, because that’s roughly what the parachute payments will cover if you go down. So the rest can be spent on transfer fees or upgrades to infrastructure.
At some point in the future, the club will be under pressure from the fans to ‘progress’ and will be tempted to keep increasing the wage bill to bring in ‘better players’. Once it gets to a certain level, it can be catastrophic if a club gets relegated as they can’t cover the wage bill and may be stuck with lots of overpaid shit that no one wants.
That’s what’s happened to the likes of Stoke, Villa etc.