uh what? the only way this was out of the blue was if you haven't been paying attention to Yes since 1978.
They also never implied that the HOF performance was anything more than a temporary event.
"All three were inducted into the Hall of Fame on April 7 — appearing alongside Howe and White from Yes – as well as original drummer Bill Bruford. (Original keyboardist Tony Kaye and the late Squire were absent.)"
What was Tony Kaye up to that he couldn't make it? Surely he didn't have better things to do? He already gets sidelined a ton you'd think he'd want to have a bit of time in the spotlight, even Bruford showed up and he's made a big deal about retiring from the pubic eye.
Just name one band "Yes featuring Anderson Wakeman and Rabin" and the other band "Yes featuring Howe White and Downes". Problem solved.