Greets!
Indeed, with demos becoming rarer we can only see gameplay footage from trailers now, which can sometimes not be representative of the game itself. I believe that marketing seems to operate on a baiting system, where they make a nice flashy eye candy, then hook a customer into buying something that they were not expecting.
A rise of the free to play model has curious effects though, with their microtransations. Some games that were single player in previous titles have now gone exclusively multiplayer due to this model, Tribes Ascend is a good example, all previous games of the tribes line had some sort of recognisable single player campaign.
What could be affecting the creation of game demos nowdays? Is it a change in gaming development, or gaming culture? Or something else entirely?