Persona 5 helped to propel the series to new levels of mainstream attention, but Atlus has always paid reverence to the previous two Persona games, as was the case when the company released a goodbye video for the cast of Persona 4 on the same day that Persona 5 was released.
The first two Persona games were similar to the mainline entries in the Shin Megami Tensei series and are rarely referenced by the later games in the series. Persona 3 was the game that established the new formula for the series, where high school students had to balance their academic and social life with dungeon crawling in order to save the world. Persona 4 improved upon Persona 3 in almost every single way, but Persona 5 was the one that became a huge hit and brought the series to new levels of mainstream fame.
The Phantom Thieves might have become the most famous Persona protagonists, but Atlus still showed some love to the previous heroes in the wake of Persona 5. Atlus released a goodbye video for the Investigation Team from Persona 4 on the day that Persona 5 was released (video courtesy of Star_Powerup on Twitter). The video shows the members of the Investigation Team waving goodbye before heading off into the light, with a final message thanking them for the memories.
Remember when atlus did a goodbye for the p4 cast when p5 released pic.twitter.com/csWdXbD2NE— Star (@Star_Powerup) November 24, 2019
It was a nice sentiment and a touching send-off for the Investigation Team, but it lasted for about five minutes. The cast of Persona 4 has since appeared in the PlayStation 4 version of Persona 4: Dancing All Night and Persona Q2: New Cinema Labyrinth. Characters from Persona 4 had cameos in Persona 3: Dancing in Moonlight, Persona 5: Dancing in Starlight, and Persona 5 Royal. Various Persona 4 characters were playable in BlazBlue: Cross Tag Battle and there is a Mii costume for Yu Narukami and a Persona 4-themed variant of the Mementos stage in Super Smash Bros. Ultimate. Atlus hasn't so much said goodbye to the cast of Persona 4 as repeatedly inviting them back into the house when their Uber keeps getting canceled.
The popularity of Persona 5 has led to the Phantom Thieves being used in numerous crossovers and this will likely continue with the cast of Persona 6 in the future. Atlus might have said goodbye to the cast of Persona 4 for the purposes of making more games set in that universe, but there is an entire future full of crossover games for the Investigation Team to appear in, meaning that the fans never truly have to say goodbye.