The Consolidate button is always greyed out in my excel quick view

The only way you can consolidate out-of-the-box in Excel is to pull a valid cube view into Excel where the cube view allows a consolidation.  You cannot simply consolidate from a Quick View or XFGETCELL, this functionality does not exist.  So if you have a "Consolidation Cube View" set up, you can bring that into Excel and assuming that cube view has "Can Consolidate = True", then the button will no longer be greyed out.  It is set up this way so the consolidation process is controlled and cannot simply be launched from any Quick View.

Here is a post in Idea Stream that you can like so this is upvoted: JIRA Ticket: PF-19835 (onestreamsoftware.com)

But also, if you search "Consolidate in Excel" in One Community you will find some other work arounds people have posted, like tying in a custom Excel button to a DM sequence to run a consolidation, but again those are customizations.