Whether the ROR trade worked out or not has nothing to do with a potential Eichel trade, though.
That's like saying the Bruins won because they made their two trades where they gave away Thornton and Seguin for less than desirable returns.
In all likelihood, this team isn't making the playoffs anytime soon with or without Eichel.
Your opinion is outright foolish.
The Bruins were able to recover from trading Thornton and Seguin because they had extensive team depth and were able to attract free agents due to their location.
When they traded Thornton, Bergeron was already a 70-point center, Krejci was in the system, so was Marchand and Lucic, they then signed Chara and Savard in the offseason. When they traded Seguin, he was their 3C on a roster that was good enough to win the cup--and he wasn't a key piece in their cup run.
Buffalo is not in a position to replicate what Boston did. They weren't in that position when they traded ROR and they won't be in that position if they trade Eichel.
The ROR trade not working has everything to do with a potential Eichel trade. The Sabres didn't have the team depth to trade him, let alone for the absolute garbage their received for him. Likewise, the Sabres can't afford to trade Eichel given that they have no one in the system capable of even replacing 70% of his offensive output. Cozens is on pace to score 21 points over a full 82-game season as a 20-year-old. Banking on him as an Eichel replacement as some people have been doing is identical to the fools who thought Mittelstadt was going to immediately replace ROR as the 2C after trading him.
This team isn't making the playoffs this year with Eichel, but without Eichel, this team isn't making the playoffs for at least another five years.
The right move is sign a proper #1 or #1A goaltender and re-sign Ulmark, then hire a successful NHL head coach, not trading Eichel or any other core roster player who isn't a UFA