I think there is some short sighted thinking here on VG... over at resetera a few of us are thinking why this might be the case.
Early 2020 (march) launch for Ps5, why do E3, too early for talk about PS5...some negativity of course but its the end of the PS4/Xbox gen whatever MS shows wont impact this gen's sales (especially if a new console is then out by the next E3). Sony will have a show in September to talk about PS5.
No point going to E3 to talk about PS4 games that everyone already knows about, people will be people and just moan.
I believe you are right, outside of one thing. PS5 will come holiday 2020, not early 2020. Change my mind...