I genuinely don't understand how you don't understand that. He would be a part of the wage structure, so of course it would impact everyone else. I'm honestly flabbergasted that people like yourself have suddenly developed this image of football agents just trying to get a half decent deal for their clients, and nothing more. The rodent at United is apparently moaning about his wages because he's on so much less than De Gea and Ronaldo. Silva at City is apparently doubling his wages in line with De Bruyne and Sterling. Its just common sense. If you were an Estate Agents and you doubled your best salesmans wages, you don't think you'd then get others asking for more?
But okay, lets say £400k a week. If Mo signs a new contract tomorrow for £400k a week, do you genuinely think that Sadio and Bobbys agents won't be mentioning it when it comes to them negotiating new contracts?
But this not a;ways the case - I've already pointed you towards the various clubs where that is not the case.
Surely we should be a meritocracy and admit that better performing players (and just better in general)
Mo's agent can point to Bobby, who has stopped being first choice, has stopped being important to our team, has stopped scoring/assisting, and say "My client is earning only 10% more Bobby, who is not first choice, doesn't bring anything to your club's international marketing possibilities, etc. Whereas my client is the best player (or top 3), is a year younger, has 40m social media followers, is easily your most valuable player with regards to marketing and sponsorship. So why should he not be paid more"?
Would you then want the club to say "no, he might be the best player in the world, but he doesn't deserve more money than the others as we have decided to be some form of socialist workers utopia"?
If Bobby's agent then comes back and says, basically "my client has none of the benefits for you as Mo, isn't first choice, but is jealous and wants more money" - we'd be right to laugh him out the room. Mo would get into almost any top team in the world - Bobby, on current (and last 18month form) struggles to play for the likes of Arsenal or Valencia.
Mane you have probably got a better argument - but again, although (unlike Bobby) he is still first choice, he is clearly performing levels below Mo currently, isn't as marketable, etc. If Mane gets kicked up to what Bobby is earning (180k) which seems fair, then Mo's agent has the same argument with the club re: his player being more valuable.