Right now there are is a little too much treasure lying around. And the fact that nobody else seems to care makes suspension of disbelief harder.
Just tweak these variables to get a good balance:
1. Amount of new derelicts and debris fields being created at any given time by spontaneous generation, NPC battles, or missions
2. Amount of NPCs that are engaged in salvaging and recovering them.
It would kind of suck if the NPCs went out and salvaged all the good stuff before you had a chance. But the game should be creating enough new shipwrecks at any time in order to replace them. Once/If stations become part of the dynamic strategic landscape, they can continually be created, captured, destroyed, salvaged etc by NPC and players so that wont be a concern either.
The time bar thing for the player salvage is not essential true-- but having it would allow for player salvage to be stolen, which might be interesting, and it would be another opportunity to use stealth and sneaking. 5 or 10 seconds just isn't that much time. And maybe it would come up AFTER all the dialogs and looting screens are displayed, and be shorter the less stuff you take, so that you don't wait for 10 seconds and only end up getting 3 pieces of metal.