Honestly Stamkos vs Guentzel shouldn't even really be an argument. If he was asking for 4 and they were offering 3 you can't tell me a GM can't get creative and find that extra million over the course of a season.
The 3 million a season was simply offered as a way for Tampa to say " we tried" even though everyone else in the hockey world knows they didn't. It was offered simply to create a narrative that could be used but has little to no truth in it.
One vs the other was never a thing, they could have likely had both but the GM didn't want Stamkos so he just made him an offer he knew he wouldn't take. Whether its hockey or any other form of business these BS " offers " are done for the same reason.
Now as far as Nashville goes, had he been making 4-5 rather than 8, most of us would be pretty happy atm. He's been worth the 4-5 this season, so anyone saying he isn't still an NHL caliber player is just trolling at this point. A top player in the league he isn't, AHL fodder he isn't either.