So maybe you can share the dates sony was originally planning and that have been/will be missed as you seem to know sony for sure is late. For reference only concrete information I know was that no launch during fiscal year ending march2020. The other bit I know is ps4 price was announced in june and I would not expect ps5 any sooner because now it's easier to generate the hype closer to the release thanks to everyone being internet savy. If sony moves too early the hype is gone before people can buy games, also launch games are likely to finish close launch(day 0 patches, games on disc maybe not even practically playable?) so showing games later is better as they are more ready.
They were probably thinking of an event before GDC again to prevent leak without giving the price after they will have a second event to talk about the price and no E3 replace by Playstation experience zone showing the game and how the OS work because it changes a lot.
I think this is the last time they will show to the public, a modified GDC conference.