I'm not a BI expert, but everyone can see the sun. Microsoft's BI tools are cheap and small and mid-size companies use Microsoft's tools just for that. Xcelsius is not a big part of BI but just say me a Microsoft tool instead for Xcelsius? One of the larger companies (Arcelik) in your home country moved a 5 terabyte Oracle database running under SAP to the Microsoft BI stack.
Also, while I am under contract and am limited by what I can say, the Federal Reserve is moving towards the Microsoft BI stack.
As for Xcelsius, one can produce much of the same output using Reporting Services and PerformancePoint Services.