I had to downvote you. Yes, there is a lot of blatant lying in sales. This is a product of paying salesmen commission and their not being accountable when they have mis-sold something. It's the dirty world of IT, and capitalism in general, to be frank.
It's the job of the pre-sales guy to keep the salesman in check, and stop him if he's making promises that can't be kept. This happened to me a lot in my short stint in pre-sales at IBM. You would architect a solution and the salesman would change it to make the price more attractive (reduce CPUs, RAM, # of servers; replace 15K HDDs with NL-SAS, that kind of thing). In those instances I always made sure there was an email trail with me stating there would be issues and it would come back to bite. When it inevitably did, I kept my distance.
However, I do need to state that not all salesmen are like this. Yes, this was the norm at IBM, due to lack of accountability, but plenty were honest and genuinely worked for the customers' benefit. You shouldn't tar everyone with the same brush.
I should also point out if you're going to buy something you should do some research and make sure what you're getting is right for you. Anyone who doesn't do this deserves what they get.