Nice article. Other than open source, one more affordable option available today is SAAS BI. Especially for small and medium companies who may not want to allocate precious IT resources for installing and maintaining the open source solutions in-house. I work for Zoho and we have one such SAAS BI solution, Zoho Reports (http://reports.zoho.com). Do have a look.
Zoho Sheet (http://sheet.zoho.com) and Zoho Reports (http://reports.zoho.com) have pivot tables since 2008. While Zoho Sheet can support 1 million cells, Zoho Reports has customers having 15-20 million rows.
Tried Zoho Creator (http://www.zoho.com/creator) and its reporting partner Zoho Reports (http://reports.zoho.com)?
Disclaimer: I work for Zoho