I tried to stay out of this, I really did but...
What the actual <kupo>
First of all, it was Matsuno-san himself who wrote the field notes. Because he writes his stories based on the state of the world, and the state of the world as he was writing Bozja was too bleak (there was also some miscommunication, as Matsuno always wanted the Blades to be cured of their tempering, and was overjoyed when the team told him it was possible, but he didn't know you couldn't cure overtempering before he twisted the Blades into their DR forms). Matsuno himself doesn't want another war story.
Secondly, it's not the end of the Ivalice content, the fact that there's no Ivalice content in EW doesn't meant it's over, both Yoshida and Matsuno have explicitly said they'd love to work together again and Matsuno has even given broad strokes of what he wants the third part of the Ivalice story to be: A story about rebuilding the liberated Dalmasca, because since he's influenced by real life events, he wants an uplifting story about people coming together. As I said the previous paragraph: Matsuno himself doesn't want another war story.
Thirdly, I don't know if you're aware, but Matsuno-san has been very busy with other projects, including a whole remaster of one of his magnum opus (Tactics Ogre Reborn, to be released in like two weeks. I greatly recommend it for people with an ounce of media literacy). And it's generally against Japanese-culture to "play with someone else's toys", so with Matsuno unavailable, no one else would touch Ivalice; however, since Matsuno grew very disappointed with the state of the world after the pandemic, he's also hinted he might be done with writing for quite a while, and in which case he would trust Yoshi-P and team with his scenario for the third act of the Ivalice story. (For everyone else, Matsuno tends to work in 4 Acts, but his comments about it make it more likely that the 3rd would be the final part in the XIV collab).
I am astounded how some people who claim to love Ivalice just completely miss the points in the original series, the XIV-adaptation, and the Ogre Battle Saga; not to mention greatly misunderstanding Matsuno-san. Matsuno and Yoshida are great friends, Yoshida is a huge fan of Matsuno's and Matsuno respects Yoshida's love for his setting and how he understood his themes. And now I will hold my tongue, peace out.