This is true. However I really feel like they (P5) should of had an E3 trailer just for exposure. One extra trailer is not going to hurt a 70 hour jrpg.
FFXV is frustrating in that there is very little actually being revealed despite frequent events, however I still think we are getting starved. Starved for that 1 5 minute trailer that will just sell the game like Versus did : a great mix of varied gameplay and captivating story sequences.
Persona 5 was at E3 in signage and giveaways but yeah they should have at least published the trailer they had on that blu-ray for the show. Missed chance for sure.
And you're right about XV too. They spend too much time saying a whole lot of nothing.