I strongly disagree. The very first e3 in 1994 was key in getting people excited about PS1 over the sega saturn and n64, E3 2005 & 2006 convinced the majority of gamers to opt for a Xbox 360 and Wii over ps3 including longtime Sony fans. The poor showing of the Wii U at E3 2012 convinced alot of Nintendo fans and curious gamers to hold off. These things do matter and how companies behave and what they present does have an affect on sales.
You have reached these conclusions based on what? There is nothing indicating the conference was a must, specially a conference in freaking 1994 when Internet wasn't as widely available. Why are people assuming that "no main conference" = "no conferences at all"? the only real change is we are not getting a stream of it, but there is a press conference for the media, plus Directs, plus demo stations, we don't get the bombastic show that we loved of course, but only we cared about it.