From what I've read, the Chargers are basically offering Bosa deal terms on par with a mid-to-late first rounder, and all he wants is terms on par with where he was selected at third overall. The Chargers cite that he wants terms that they have never given to any pick since 2011, but that's disingenuous because they haven't picked anywhere near third overall in that time frame. I see no reason why a team would risk destroying their relationship with a player when all he wants is the same concessions that any other team would give to a top five pick. It just seems very shortsighted by them.
The press release they put out was pretty obviously damage control to try to shift the blame to Bosa by painting him as greedy, even though all he wants is what he would have gotten from another team had they had the third pick instead.