id be 100% willing to believe Scaleface had Season 4 not been announced. I think that was probably their initial plan, but either do to some delay, wanting to give wrath more space, or giving Dragonflight more interaction time as they know they need a good xpac. Could be a combination of the above tbh.
I think its likely they wanted more time, but could release it this year if need be. Wrath was releasing so within the last month or two decided to make a season 4 and give themselves 3-6 more months to get it right.
They know the xpac needs to be good.
Also, I don't know why people think Wrath is releasing September. Did Scaleface say that? If so, I think its likely they will push it back a month or even two now that they have more dev time for Dragonflight.
My prediction is this.
Wrath Classic- Late Oct/early Nov release.
10.0 Prepatch- late Feb 2023.
Dragonflight launch-Mid March 2023.