Long term deals in Free agency only work if you’re signing future Hall of Famers (or players close to that level). Freeman, Betts, Scherzer, Ohtani and maybe even Seager are all good candidates. Otherwise you’re just signing an aging player to wind down his days. Is Burnes a future Hall of Famer, or at least close? He’s 30 and in 4 yrs as a starter has been worth 16.5 bWAR. He might be able to post another 30ish bWAR in the next 7 years, but it wouldn’t be a shock if he didn’t.
Plenty of teams have gone as big as LA with free agency and been complete flops, too. In fact, it’s probably the more likely outcome.
Also Yamamoto is a different case, as he wasn’t as old as most free agents. Thats a big factor.
So Will Burnes be another Scherzer? Or another Price? It costs about a quarter of a billion non-refundable US dollars to find out. If he is, then whoever signs him reaps huge benefits. But if he isn’t, that type of deal can keep a team non-competitive for nearly a decade. And maybe longer…