Perhaps this example will serve:
The cops arrive at a bar fight. There are 20 people there. There is 1 person seriously injured an unconscious and a couple of people who were obviously involved who are not cooperating.
There is reason to believe that of the remaining people, a 1 or 2 others were involved and the cops intend to find out who they were and arrest them for disorderly conduct or possibly more serious charges if the facts warrant. The cops also believe that almost everyone saw what happened. For the sake of this example, there is no "duty to intervene" and there is no sign that anyone is legally drunk, so those who stood by and did nothing will not face any criminal charges and neither will the bar owner or his employees.
For this example, assume that the witnesses and those involved in the bar fight don't know each other and that their cooperation or failure to cooperate with the police won't have any "social consequences" one way or the other. Whatever choice they make, they will not be banned from that bar and they won't gain or lose any friendships or business relationships.
Also, assume the cops have a reputation for being professionals who act professionally (contrast to the Waco "Twin Peaks" incident).
The cops detain everyone on-site for questioning, with the intent of letting all of them except the few guilty ones go as soon as they get things sorted out.
It's getting late and people want to get home so they can get some sleep so they won't be tired at work the next day.
If everyone clams up, the police will probably keep everyone there for a few hours before "giving up" and will get everyone's name and address. All potential witnesses - including the as-yet-unknown guilty parties - will get summoned to a grand jury or to a similar proceeding if it's a misdemeanor offense, and eventually (unless people forget, innocent people lie, guilty people lie in a convincing manner, or innocent people fraudulently "plead the 5th" to keep from testifying) things will get sorted out and the facts will come out.
It is clearly in the short term interest of those who were not involved to cooperate and give accurate statements right then and there. If they do, those who were not involved will go home sooner and may avoid having to go to a grand jury. Those who were involved will spend the night in jail and will know they will likely lose at trial so they will probably plead guilty, which means the witnesses won't have to take a day off of work to testify at trial.
All in all, for the innocent-bystander witnesses, it's a clear-cut case in favor of cooperating with the police if they are only considering their immediate and short-term need to get home and not have to waste time in court in the future.
Note - this example probably has flaws in it. However, if you are smart enough to spot them, you are probably smart enough to come up with many better examples that show that, on the whole, it is better for a person who is both innocent and who has every reason to believe he is not "a target of an investigation" or "a target of the police" to cooperate.
As I said in an earlier post, there are situations where it is clearly NOT in a person's short-term interest to cooperate with the police. My list may have been incomplete. However, once it is complete the remaining situations will be common enough that, unfortunately (or fortunately, depending on your perspective), my general statement still stands.