True. It seems the only way we may be able to pinpoint any individuals involved is when the government decides (if they ever do) to open the sealed documents related to the JFK assassination.
That said, I think some reasonable assumptions can be made as to who was involved, and the reasons why.
One conclusion everyone that looks into the JFK assassination should be able to arrive at is that Oswald didn't act alone, and it's quite possible he didn't even fire a shot at the President.
It's also obvious that the government played a role in the cover-up of the assassination and may have even played a role in orchestrating it.