The Nationals want to play off the lack of movement at the trade deadline as a positive. They don't need any help. They aren't going to make a deal just to keep up with the Joneses. They are confident of winning with the guys already "in the room". These guys are good enough to win 61 games so far, they can make the playoffs. It's hard to argue with that but here goes.
It's not about being good enough, it's about realizing you can always be better. The Nats have had the "problem" that there is no glaring weakness with the team (that's not exactly true - catcher is a glaring weakness but it's also a spot almost impossible to vastly improve by trade) There isn't a singular focus point where you can say "fix this and the Nats will be much better", but there are places that the Nats could improve. By doing nothing the Nats are implicitly saying they don't believe that's true. They think the catching situation is fine as it is. They like their MI backups to to be punchless bench bats. They believe the guy who hasn't hit for the past few years and hasn't shown any particular acumen for pinch hitting over his career will keep coming up with the big hit, and that the rookie call-up that strikes out all the time will come up with the big blast. They are betting that there will be no more big offensive injuries for a team that's been plagued with offensive injuries all year long.
It's almost as if because this wasn't supposed to be the year the Nats were a dominant force at the top of the NL East, that it's ok for the club not to go all in. This is a gift year, let's not do anything stupid, and let's set ourselves up for next year. That bush over there is so full of birds, who cares if this one flies away? Playoffs aren't guaranteed even for teams that appear set up to make it. Look at the Red Sox. Someone gets injured, someone else underperforms and suddenly your 90 win team is an 85 win team and you are on the outside looking in. The window is already small, 3-5 years for most teams, that to not take every year you are playoff contending as a serious chance to win a title is asinine. The Nats are good enough that the cost of "being serious" was small. Few were asking to trade the farm for a rental pitcher, or an CF with potentially no place to play. It was about making a couple gambles on tossing some weak prospects for some bats that may be able to show their old talent one last time. Betting on a couple of new has-beens as opposed to relying on the less talented has-beens and never-will-bes you are currently employing.
The lack of movement isn't a death knell for the Nats. This all should work out fine anyway. As I've been saying all year the starting pitching is that good, that this team shouldn't fall out of the playoffs. They have a series lead on the Braves who have shown a tendency to lose when it matters most. The Pirates have been playing above their heads all year. The Giants and Dodgers have 9 games left against each other where either one team beats up the other or they both lose 4-5 games. Once in the playoffs, even in the undesirable Wild Card role, anything can happen.
The Nats team will win enough games. But wouldn't you have liked to see the team go out trying everything they reasonably can do to win just one more than "enough"?