Earlier quoted context omitted.
It's all just pivot tables, in the end. Excel solved most data slicing/drilldown problems years ago. Only issue has always been data size limits and access to live, up to data data (though Excel's also been able to hit external OLAP services for data for a long time too).
And the data size limit is excel is stifling. 1m maximum rows? That can get filled very quickly.
http://www.microsofttrends.com/2014/02/09/how-much-data-can-...
If that's not enough you can do SSAS Tabular + DirectQuery (although to be fair, that's no longer "pure Excel", but an end user likely doesn't care):