Thats not the same, though - dont confuse "getting to play the content" with "getting the rewards of said content". You can do savage right now - access to it has never been easier! Since ARR more and more options were added to make access to this content easier - putting it in DF, allowing to queue for it without a full party, adding PF, adding options to DF/PF to allow to "filter" for groups...
Adding FC-exclusive content would do the opposite - it would make content more difficult to acces in the first place, before even considering how easy it would be to get the rewards.