There is no secret, Insomniac has enough people to develop 3-4 AAA games at the same times, while most other AAA studios only had enough people to develop only 1 AAA game at the same time. That allowed Insomniac to release games more frequently than the other studios.
Jimbo decided to highly increase the manpower of all their other studios to allow them work in more games at the same time in a Insomniac way, so in the future they'll be able to release games more frequently.
That is the reason of why XDEV is working on way more games than ever before, why SSM, ND, Guerrilla, Firesprite or Bungie are working on multiple projects at the same time while they didn't do it in the past. Or why XDEV, or specifically their Japanese team (the former Japan Studio 2nd party team, now in charge of the SIE 2nd party games developed in the whole Asia) are working on way more games at the same they ever did before.
Seems we have another flatearther who rejects reality and says that the nonGaaS games don't exist or aren't shown. Sure, the Spider-Man 2 previews we saw yesterday never happened. Rift Apart, TLOU and Returnal weren't released on PC a few months ago. Games like Death Stranding 2 or the China and India Hero Projects never were shown and games like Stellar Blade or Convallaria aren't announced for this year.
And well, let's act also as if for some reason they wouldn't also to strategically spread them in their release calendar and marketing slots with 2nd or 3rd party exclusives or big 3rd parties and indies with marketing deals. Most of them non-GaaS btw.