The cap is set up so that teams can't have too many elite players, unless they sacrifice depth.
I'd rather sacrifice depth than sacrifice the Defensive Player of the Year. If we can't replace depth, we're doing a poor job of identifying and developing talent.
Theoretically, things could work out, and Donald might not be the straw that breaks the camels back. But it is a fact that the Rams have 3 free agents on their OL this coming season, and it's not clear if they have any quality replacements on their roster yet. Plus holes likely to emerge elsewhere.
Well, we drafted 3 OLs. We have the Draft next year. And we have FA (while still possessing plenty of cap room). I also expect we'll try to keep at least one of the two young OLs (Hav and Jamon).
The current dynasty in the NFL is the Patriots, which are known for trading expensive players for draft picks. Not all of them, but a number of them, so I don't think recent history supports your thesis. The Patriots would keep a couple of elite players, but not all of them.
Recent history perfectly supports my thesis. The Patriots retain the players who are elite and key to their scheme. They trade or let walk in FA the quality players who are replaceable. And then they replace those players with younger, cheaper players. Look at which guys the Patriots have kept around: Brady, Gronk, and Devin McCourty. All three guys are top 5 players at their positions who play vital roles in the Patriots' success. Look at the guys they've let go: Chandler Jones (trade), Jaime Collins (trade), Logan Mankins (FA - Age), Nate Solder (FA - Age), Dion Lewis (FA - Replaceable), Wes Welker (FA - Replaceable), Malcolm Butler (FA - Replaced), etc.
Donald is our Gronk. He's the best player at his position and one of the best players in football. He's a guy you build a scheme around. He's one of a not very long list of non-QBs who changes the landscape of a game. Donald isn't the guy you let walk. He's the guy you keep. You aren't going to replace an Aaron Donald, but if Kromer and McVay are as good as advertised (and I think they are), you can replace a Rodger Saffold or a Jamon Brown or a Rob Havenstein.
Can we agree at least that there is some dollar amount that signing AD for would not make sense for the Rams? He's a great player, but I want a great team. And having a great team requires depth. Yes, that means having good but not great players in spots, instead of having a great player and a number of well below average players.
That's a given, but I highly doubt that Donald has priced himself out of this atmosphere. Both sides are posturing right now.