Because blockade attempts are unwanted. I think it's intentional design these things cannot be achieved, and I support that decision.
Possibly... But:-
1) There's no reason why a mechanic could not introduce to offer them in a structured format. eg: For a community goal, or as a Powerplay task.
2) If (1) proves viable why not employ this mechanic when a systems situation reaches the appropriate position?
But in truth it doesn't matter if it was a blockade being attempted or not, it's the fact that in truth "
nothing" can be attempted... The mechanics are too shallow and simplistic.
As it stands the ED Universe is shallow, filled with a bunch of simplistic mini-games, supported by some very simple mechanics. Surely we need more sand in this sandbox, and more ways to play with it? And if this means we can get to some interesting emergent gameplay? Great! At the moment, we really don't stand a hope though. All that can be achieved is to bang your head on the bottom of the sandbox through just 2mm of sand. ie: What we saw at Hutton.
Do you not think last weak highlighted some weaknesses and areas that need attention/improving? Are you not a little worried there's no suggestion FD see this as the case?