Re: hopefully...
An important limitation of Calc is its max number of columns: 1024 I think, vs the 16k+ of Excel
Depends on which version of Excel you are using. The increase from 256 columns in Excel 2003 to 16k in 2007 was one of the features that made me upgrade. I suspect that Calc's limit, whilst insufficient for heavy users is probably good enough for many.
I suspect one of the problems with MS Office is that MS have stretched the boundaries to overlap with more capable third-party products. So for example, Word does 'large' documents sufficiently well for many businesses not to invest in document tools, such as those that Xerox were selling in the early to mid 1990's and which the world has largely forgotten about...