Some of these are a function of the football transfer funds being recycled of course. selling clubs fully aware of how much buying clubs may have banked. And that has always been the case. But some new trends too this summer. Not sure any of it is healthy.
Definately not healthey and a deal for pyramid support has to be made soon. The money has to trickle down as its no longer getting there via player sales. It even seems reversed somewhat as lower league clubs seek Premiership academy players. A measly 6k for stadium renovation isnt support.
Sell-on clauses have been there, but I think they're more popular than ever. I'd be interested in the percentage of deals with a sell-on or buy back clauses. Teams who may be ok with parting with players now want to retain some interest in future transfer value.
I'd guess sell-on clauses have gained popularity because playing careers have greater longevity these days, and it's possible a player even in their 30s will be sold for big money, especially with Saudi clubs increasingly active in the marketplace.