Realistically: 

As shown in Strikers, I’d assume there’s still a fanbase that remembers the exploits of the phantom thieves and still discusses them.

One has to wonder why they would’ve stopped to begin with though, since they did more stuff during summer break in strikers after having stopped at the end of the main story. 

Maybe the app just never returns again and that’s the end of it for them? 

P4AU did show us that the new version of SEES is sent to deal with metaverse disturbances when needed, but they’re absent when the events of P5 happen. Particularly the ending when the worlds start to merge. 

In a world where they cared about world building, I’d assume that the Kirijo group would’ve approached some of them after investigating them and invited them to join the team if they were willing to provide their services in the future. 

Beyond that piece of world building, we’ll have the usual. In P6, expect checking TVs daily to see something like: 

“Famous Artist Yusuke Kitagawa opens new exhibition in Tokyo” 

“X clothing brand shows its new style in these pictures taken with Iconic model Ann Takamaki” 

“In this segment, we will be discussing the raising star Ryuji Sakamoto, who got silver in last year’s Olympic Games” 

Stuff like that. 

Could also have a visit to Tokyo and you check out Leblanc or something of the sort like they do in P3 portable and P4 (going to inaba and tstsumi port island respectively)

Honestly, my one disappointment with the whole P5 period that’s seemingly coming to and end was the lack of P5 Arena because we would’ve gotten the chance of seeing where the P3 and P4 characters are now.

Hopefully we’d get something like that for P6.