Actually, there are a whole raft of issues you are conflating here. You need to ask why Excel is so widely used. It is used as:

Use Case 1: A basic spreadsheet for data manipulation, with no extensive macros or VBA involved. People use it for vlookups and other formulas they find useful.

Use Case 2: As a statistical analysis tool to crunch data.

Use Case 3: As a software platform, making extensive use of Visual Basic for Applications (VBA).

So here are the issues I have with your statement that Excel "is far and away the best, fastest and most robust spreadsheet out there"...

Fallacy 1: Excel is the best technical option

Excel is not necessarily the fastest spreadsheet out there for all operations. In many cases I believe it is still very fast, and beats LibreOffice under certain document loads, but this is often not by much and in fact there is ongoing work towards locating problem documents and profiling of LibreOffice code to remove bottlenecks. In fact, in LO 4.2 many performance bottlenecks were largely solved. [1]

At this point, I do think it's largely a myth that Calc is dreadfully slow. Even if it should be found that there are performance issues, however, I know that the LO community, and in particular Collabora, have a good story around their ability to use valgrind to benchmark and analyze results. As a normal part of development work, Collabora are often provided with documents that they analyse and contribute performance improvements into the core LO code base.

There are many, many errors in even basic statistical functions in most spreadsheet applications, but Microsoft Excel is particularly egregious. However, IMO the LO devs are more thorough when it comes to this [2][3]. So for use case 2 (statistical work) then I think it's not suitable (actually, for any stats work, why not just use R?)

So if Excel is not necessarily better than Calc in terms of performance, accuracy or overall robustness (you might want to look at a feature comparison here: https://wiki.documentfoundation.org/Feature_Comparison:_Libr... - quite informative I think!) then really the issue is that it's being used as a platform for VBA development.

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Fallacy 2: Excel is the best integrated option for office application development work

So now here is the rub: this has been something causing Microsoft vendor lockin for years. Expertise in financial firms around Excel is very high, and often quite extensive custom "solutions" are based on Excel spreadsheets, but almost always via VBA.

But... Microsoft's VBA diverged from Visual Basic in VB6, and Microsoft have been struggling to know what to about it ever since. I point out that they removed support for VBA in Office 2008 for OS X, but then had to put it back in due to market demands in Office 2012, and I also note that the only update to VBA7 is to introduce actual pointers.

So basically, this will only be a competitive advantage for so long for Microsoft. As the marketplace starts to open up - and it is! - firms will be looking for solutions that either do NOT rely on Excel or VBA and that can integrate with better scripting languages, like Python.

In fact, I've been hearing that a lot of financial institutions are getting quite concerned with data silos: these are usually in Excel, haven't been audited, aren't integrated into the business' DW, are isolated and thus cause problems with transparency and decision making, and are almost NEVER documented meaning that should the maintainer leave then that spreadsheet will either be used and unmaintained, or will need to be redeveloped anyway.

So really, the key advantage Excel has is ubiquity, and really only then because of VBA, but that's a double-edged sword and eventually businesses will migrate away from it.

1. https://wiki.documentfoundation.org/ReleaseNotes/4.2#Perform...

2. http://lists.freedesktop.org/archives/libreoffice/2013-April...

3. So far as I'm aware, Excel's RNG is now using The Mersenne Twister algorithm in Excel 2010 and beyond, but that's not officially confirmed from Microsoft. It's very hard to be certain of what is being used without such a confirmation, and given that Microsoft has form in releasing a flawed RNG update already (which they never got around to fixing for years and years!) I don't know how you could consider Excel to be "more robust" than LibreOffice.