24-70mm f/2.8

Hello. I am soon looking into buying either the EOS R, the R5 or the R6 (depending on the upcoming announcements). I am also going to buy a 24-70 lens, because it seems like a versatile tool to have (I only shoot stills). I've heard many good things about the new RF lenses and would like to own...

Can anyone explain to me why Canon skirted it's long time loyal DSLR customers by not making a 24-70mm f/2.8 with IS and instead made one for the RF Mirrorless? Most of the other lens manufacturers have included anti-shake for their 24-70mm f/2.8's.