It is crystal clear that you are clutching at straws.
Negotiations leak regularly when there are disagreements causing stalemate or conflict. For example we know Liverpool have been trying to tie Salah, Van Dijk and Trent down, but they are not signing because the terms are not favourable to them yet. In Salah's case we know Liverpool did not offer him a contract as at November last year, because the player publicly came out to confirm the rumours that had already been swirling around. We know they changed tact in December and initially offered a 1 year extension, which has now been upgraded to 2 years. However we also know that both he and his agent prefer a 3 year extension because they've also let that out.
Top footballers have been celebrities for quite a while and there is literally nothing that doesn't leak especially when it has the ability to capture the public's interest. So no, if a top player had been offered a 5 year contract by a club and he insisted on 4 or even shorter and they both failed to agree, we'd have heard just like whats happening with Liverpool.
Now, against my better judgment, I'm going to explain why it's not logical that the club offered a 5 year contract to Saliba and his agent insisted on 4 years instead, which you initially claimed was the more probable thing that occurred and is what I should have assumed if I didn't have a "grouse" with the club.
Firstly, the majority of player agents (especially those representing players in top leagues) do not make most of their income from transfer fees as most of the public believes. Its a notion that the press has encouraged, but it hasn't been true for quite a while. Player agents are paid a % of the salaries they negotiate for their clients, capped at 3-5% currently, but as high as 10% pre 2023. Agents who earn from transfer fees, are either agents acting on behalf of the buying club (capped at 3-7% of wages currently) or agents acting on behalf of the selling club (capped at 10% of fee currently). So to make it clear, in a typical transfer that involves two clubs and a player, all 3 parties can have agents representing them.
Now a big reason why this notion of agents pushing clients to seek for transfers exists is because we have had a few high profile cases where a player's agent also acts as the agent for either the buying club or the selling club. In fact we have had cases where a player's agent acts for all 3, and is pretty much where the greed in the system is exposed. Anyway, FIFA has rules put in place since 2023, which does not allow for this to happen anymore and a player's agent can only act for 2 parties. Though this rule was enforced in October 2023, FIFA had since announced it by 2022 after a few scandalous transfers, especially those linked to one super agent in particular, Mino Raiola, whose agency executed the Pogba and Haaland transfers. The greedy fucker also happened to be the president of agents association called the Football Forum.
So going back to Saliba, his agent at that time and till now is Djibril Niang and he isn't even close to what you will call a super agent. Tranfermarkt suggests that the talent he manages is valued at €110m, with Saliba accounting for €80m of that total. So clearly, Saliba is his cash cow and he will want to ensure the income he gets from Saliba is protected for as long as possible.
Like I pointed out, he gets paid as long as Saliba earns a salary. He gets paid more every time Saliba gets a salary increase. Now note, with the examples I gave of Gomez who has been at Liverpool for almost 10 years, yet has signed 4 contracts of 5 year lengths; or Haaland, who has been at City for less than 3 years but has signed 2 contracts totalling 16 years; it is clear that getting a salary increase is not dependent on the length of your contract or moving to another club, but how well a player performs. It is also clear that longer contracts with good terms benefit agents because if for any reason there is a drop in their player's performance or he is injured long term, the club cannot reduce the salary and both the agent's and player's income are safe. However, signing a shorter contract and loss of form/injuries/relevance occurring, would definitely lead to a club offering less wages in a new contract that's if they even bother to offer one at all... and if you insist on examples, I can definitely give.
So once again, for a top footballer earning top wages, the longer the contract the better. The same for his agent as it does not preclude the player from earning a bigger contract and definitely does not stop him from enjoying a big money transfer as no length of contract will stop a top player from moving to a top club of his choice as the Mbappe debacle showed and PSG learnt the hard way.
Now finally to buttress the point on longer contracts being preferred, I mentioned how Haaland's initial transfer to Citeh was seen as a bit scandalous. His agent at that time, Rafaela Pimenta and his father made a rumoured €40m by doing what I mentioned earlier and acting as agents for the various parties. His dad's relationship with Citeh was one of the reasons why this was possible but immediately after that transfer FIFA announced they were stepping in. Now, till today, Haaland is still represented by Rafaela's agency and she was the first one to let it slip as far back as 2023 that both her and Citeh were working on something to ensure Halaand's proper value of €1 billion would be reflected. So, I ask, is not strange, or should I say illogical, that someone who made a killing from moving her client to another club just a few years ago would allow the world's hottest striker to sign a contract that sounds a bit like modern-day slavery @ 10 years, with previous buy-out clauses frozen (until after 5 years) which was the loophole she exploited so successfully @ Dortmund. Is it logical that she had been working with Citeh on this for more than a year?
While you can keep up with your view that our suits offered him 5 years or more and his agent rejected it, asking me to accept it as more logical/probable is tantamount to saying I should accept the proverbial saying "a bird in hand..." was built on a fallacy. Maybe I could, but definitely not with responses like above.