Why is PIE more centum than satem?

From: michael_donne
Message: 12226
Date: 2002-02-02

I notice that pretty much all of the PIE words are reconstructed with
a k or k' instead of a s? Why is that?

If the centum/satem divide is now considered to be from about the
same time and if the IndoIranian languages are among the oldest
recorded (if not the oldest if Hittite is questioned a la Beekes),
then is it possible that PIE may have had some satem forms of these
words instead?