That's not the market inflation though. If the player being sold was available at an external club, you'd have bids far higher than that coming in for the player. So therefore, why should we accept a lower value? None of my players are shit, none of them are cast offs. All play first team football for their clubs and will continue to rise, so why should I therefore take a huge hit in their sale? Fact is if you make shit offers then don't expect them to be accepted. I'd rather keep hold of them than accept crap low offers.
Take Korb as an example. 23 years old, 88 rated, plays regular first team football for Gladbach yet he's valued at 6.2m in my squad. Seb Rudy who's at an external club and 2 years older is valued at 7.8m. So Korbs actual value is at least 8.5m before any inflation is added on. But some managers will take the piss by bidding low despite Korb being in line to be raised up to 89 by December. Which would bump his value above 10m.
So either you bid smart and fair, or you just piss people off. A fair bid for Korb would be in the range of 9.5-10m, that takes into account market inflation and his rise to 89, while also still netting the bidding club a profit as Korb would be valued in the range of 10-11m when he hits 89.