I've had that happen repeatedly as well, both now and "back in the day". I have no idea if a higher or lower proportion of the tougher questions are being answered now than they "used to be", but my sense is that it is about the same. The tougher questions are just tougher to answer; that hasn't changed through time. What I do know for sure is that a much higher proportion of easy questions can be answered by searching google and following one of the first few SO links, which is valuable.