And Sony obviously doesn't want players to be overly excited over it's games at some random point in February.
There is a fundamental problems with big exciting shows for Sony:
1. This excitement will not last long and will be quickly overwritten in week or two by next batch of news on internet. Brain has limited capacity and information overload led to shorter attention span when things are replaced and forgotten much faster.
2. Nature doesn't like to reward simply for repetion, so any excitement builds a resistance, making it harder to get excited again. The higher the excitement spike, the bigger the resistance, leading to a burn-out of interest
3. Sony goal is to sell games, not excite fans, so the whole excitement part should be structured to get interest and maintain it all the way to preorder/launch
4. People, on other hand, became overexposed and with their short attention spam become junkies, seeking another spike of excitement and even actively demanding it, even if it's detrimental to long-term interest
The whole notion "make a grand show on E3, feed some news to keep flame over slow summer month and then sell games in autumn" does not work in internet era where information flow are so high that any excitement overwritten and effect dies in mere weeks.