The problem with your line of thinking is that you assume they just created something totally fake without any ambition to actually reach that point.
Do you think they just faked that 2012 demo to give people false hope? Hell no, that's exactly what they were aiming for. Their ambitions were simply too high and, for reasons unclear, they weren't able to meet that objective.
This mentality that all these developers are out to fuck you over really makes me shake my head. Publishers might behave that way, but I don't believe the creative people working on these games intend that at all.
The fact that Watch Dogs was shown so far in advance as a game intended for platforms which didn't yet exist only makes their situation more difficult.
The problem with your line of thinking is that its OK to make a promise to deliver what they initially show, then be clear of any and all criticism when they can't.
Put up for STFU. No one forced them to raise expectations unrealistically high. Hell, most of life and business is managing expectations after all.