Considering Microsoft recent involvment with R I have the crazy hope that future versions of Excel will be shipped with R as a scripting language.
However there are other family of analytics tasks which can be summed up as "decision analysis". Taking regression models (for example, maybe even built in R) and simulating them under different inputs, getting quantiles, sensitivity, etc. This goes much further with multiple sets, multiple outcomes with decision trees (NOT regression trees/CART) and even further with solvers. Excel is the best option in those tasks most of the time because of quick data entry and already built output reports and interfaces.
"I am worried by the number of people that couldn’t tell that this was sarcasm"