I was particularly disappointed with re:Invent for this reason. Everything I attended could be found in blogs that had been published for years and very few "higher level" sessions that were still very trivial. Most of those weren't even discussions, just follow a lab sheet that you won't have time to finish or doesn't work at the time. I'm not sure if it was always this way, but the only people who seem to benefit at all are those in sales-oriented position. It is basically only good for meeting people and you may as well just skip all of the actual content to pursue that.
It was the first real conference I've attended (luckily not at my expense) and will likely be my last.