Let's combine 2 very hypothetical scenarios. Assume the Nats didn't shut Strasburg down. The Nats make it to the WS, and Stras blows his arm out in game 7. The Nationals win the Series. Strasburg's career is over. Worth it?
For the team and the fans, most likely. Flags fly forever.
Not exactly the same thing, but the Raptors traded away one of their most popular players ever for 1 year of Kawhi, and it paid off. I don't know anyone that thinks the fact they won't be in title contention again for at least a few years didn't make the trade worth it.