Could Excel ever become obsolete?

I read this post over at Smurf on Spreadsheets about the possibility of OpenOffice.org ever taking a significant market share away from Excel.  It's a compelling possibility.  OOo is free and has most of the functionality of Excel (at least the functionalities that are commonly used).  The reason I personally haven't used it much is that there is a lack of support for VBA, which I do a fair amount of work in.  Although, as Simon gestures, a few releases from now OOo could be VBA compatible.

Given the economic times, it is not a stretch to think that a free piece of software could begin to dent Microsoft's market share.  

But, I'm just not seeing it happen quite yet.  I work for an accounting firm that does a lot of work for non-profit organizations.  You'd think that of all people/entities looking to cut costs, non-profits would be jumping at the chance to use a free office suite.  None of the clients that I work with use OOo.  I would venture to bet that none of them have heard of it.  I think that OOo has a vast reach in very tech savvy communities, but outside those rings it finds itself very easily pushed aside.  A while back they even had advertisements in many of the buses around town, but I don't think they really got their point across.  People just don't know about it.