STP needed/s a massive hit to legitimize this version of the band. That's what it really comes down to. Out of Time gets lots of play, but it's not a massive hit. Unfortunately, this change has occurred way past STP's popularity, so unless something changes, Chester's version of the band will not have the same legitimacy as Scott's version.
The reason it worked with Van Halen was 1) VH were at the height of their popularity, and 2) they followed up the first single off of 1984, Jump, which hit #1 on the rock charts and the Hot 100, with Why Can't This Be Love, which hit #1 on the rock charts and #3 on the Hot 100.
To put it more directly, they followed up their biggest hit ever (still) with their 2nd-biggest hit ever (still). So the reason there is a Sammy/Dave argument is that they had hits with both singers.
So in order to sell, they need a hit at least as big as Sour Girl.
