Re Felix/Hazard* - yes, market forces absolutely do dictate that Felix is worth that. If that is what x offers then that is what he's worth. Supply, demand and the amount of money available to potential buyers determine transfer fees, it's no different from 50 years ago. You can argue that Hazard is better and more established but that does not change the fact that it's the market that determines how much Felix is worth. If there's multiple clubs that desperately want to sign him and they can afford to pay that fee then that is what he's worth. It's no different with Hazard* - if there was a number of clubs after him and they were willing to pay x then that's what he's worth. As it happens, he's only interested in Real so there's no auction, Real know he has 1 year left on his deal so the pressure is on Chelsea and at 28 years old Real and Chelsea know there's only a few good years left in him so will adjust their offer/demands accordingly.
*The fact that Felix is 9 years younger and likely to earn no more than 50% of what Hazard will get at Real actually means that if he's sold for the same fee, in reality he's cost significantly less.
Re Felix/Ronaldo. Back in 2003 the top sides were turning over between £120-170m per year. This season just gone Utd will turnover around £600m and there will be multiple other clubs turning over as much if not more plus your City's and PSG's of this world where money is no object. Purely from an inflation point of view £15m in 2003 is now around £60m odd today, throw in the increased levels of competition and that figure is even higher. As for Ronaldo's stats or how established he was back then compared to Felix - it's no competition, Felix is miles ahead of where Ronaldo was back then. Not that I believe that Felix will be sold for £100m but it's quite easy to see how these figures have been reached and it's not that expensive relative to historical deals and the market today.
Re Maguire. I used him as an example because last summer you were complaining about the huge increase in the fee Leicester were supposedly demanding. It's not debateable that Maguire's as good as VVD, he's not and there's not a CB in the world that's nearly as good as him but Leicester are absolutely within their rights to demand whatever they believe Utd or whoever else would pay for him. He could have 1 year on his deal or 5 years on his deal, it doesn't matter. All that matters is how much they want to keep him and how desperate x is to sign him.
And where on earth did I say Maguire was better than De Ligt? I've not commented on ability. How much somebody is worth and how good they are, are two different things. As mentioned above re Hazard, somebody's fee is determined by many factors, not just ability.
And no, I did not say a 300% profit was modest. I questioned whether you believe Leicester (or whoever) should take punts on 5 players, lose out on 4 of them as they're not a success and then accept a modest profit on the 1 that's successful? As above, you were complaining about the £60m fee for Maguire last summer so clearly you believe they should have sold him for much less. As I said last summer and again earlier, Leicester should demand every single penny they believe a buyer will pay. They took the gamble on him and nobody is going to be sympathetic with them when they try to sell a flop and offer then 80% of what they paid and when they try to replace Maguire they're not assured of success with that so they need to be compensated accordingly.
As for there being less risk for Leicester or similar. They're buying cheaper players because they have less money. Leicester's turnover the season they signed Maguire was just under £160m - he cost over 10% of their revenue. And guess what, Utd's turnover that season was £590m. Utd paying £60m on him would be just as expensive to them and just as great a risk as Leicester paying £17m.
Frank your whole argument is bonkers.