I think that's somewhat wishful thinking on your part. It's very difficult to keep a player that wants to leave and while the clause may not apply to Chelsea, it sets a benchmark in the players eyes and if Chelsea were to offer that amount (or slightly more) then good luck keeping the player happy when turning that down. Furthermore the player (or at least his agent) isn't silly, if Palace are playing hardball with Chelsea then they'll use the interest of a CL club to force Palace's hand. Not that I believe there's any chance that Olise wouldn't ultimately move to City/Arsenal/Liverpool if pushed but I you can guarantee that he'll be telling Palace that he'll join them if Palace don't accept Chelsea's £65m bid (for example).
Anyway we've gone down a long hypothetical path here. I've no doubt Palace would like to keep their best players, although I suspect there's an element of pragmatism there and they'll realise that they can potentially improve the side by cashing in on one or two and I suspect the fact that any release clause may exclude non CL clubs will ultimately not count for a great deal.
