Lol, those are literally the best relievers in the game. Finnegan isnt them.
Meanwhile, Jake McGee, Jeurys Familia, Joe Kelley, Alex Colome, Bryan Shaw, Trevor May, Jake Diekman, Matt Barnes, and Will Smith were all once good and fell off a cliff.
Relief pitcher is the most volatile postion in baseball, if not all of sports. Guys flame out all the time. Four years ago, Kirby Yates, Seth Lugo, Brandon Workman, Felipe Vazquez, Arolids Chapman, Nick Anderson, Hansel Robles, and Ken Giles were in the top 10 best relievers. Yea .... hows that working out now?
Someone is offering you a top 30 prospect in their system for Finnegan, you absolutely take it. Then you call up someone and see if they have the goods. Thats what developmental teams do.
One thing those guys you mentioned have in common, long careers. Here is what Finnegan has done so far:
2020 - Innings Pitched - 242. ERA - 2.92
2021 - Innings Pitched - 66 ERA - 3.55 11 Saves
2022 - Innings Pitched - 66.2 ERA 3.51 11 Saves.
He'll not only be a valuable piece when the Nats get good again but this year and next also. The Nats aren't going to overwork young pitchers like Cavalli, Gore, Gray, etc. The pen will be critical.
It's laughable to think the Nats can rebuild trading useful pieces both now and when they get good again for some other teams between 20 and 30 rated prospect and try to catch lightning in a bottle. This is not yesterdays MLB. The pen has to take over a game usually from the 6th inning on in todays game.