How does a discussion about Excel become a Mac vs PC arguement...

only at the CPA....
You are getting to the crux of the problem for Mac...
1) It cost more to develop for Mac users - due to Apples insane thinking that people will pay a premium for their machine because they are better... Wrong... Even if they were twice the machine, hell, even 3 times the machine... it's all about economy...
2) Since they have such a small percentage of the market... a developer can't afford to spend a fortune porting to the Mac... Hell, it's sort of sick, but if Microsoft hadn't developed a version of Office for the Mac... I think they would have folded a long time ago... they need more than just the fringe artist buying to sustain themselves...
I watched an excellent program on PBS by Bob Kringley a few years ago... It pretty much explained (not in black and white) why PC's won the market.
For those of you too young to remember the days before PC's... There were several small companies making Personal Computers (not what is now thought of as Intel PC). Apple, Tandy (Radio Shack), and IBM were pretty much the big 3. IBM developed the PC and PCjr... but, they made a crucial mistake when it came to their relationship with Microsoft. Bill Gates is a very savvy dude... IBM contracted with his young company to make a basic interpreter - because IBM figured EVERY PC should have a programming language to make it useful (and marketable)...
Well, M$ wrote QBasic for DOS... IBM needed to get DOS (Disk Operating System) for their machines... But the company who wrote it, for whatever reason wouldn't sign the non-disclosure agreement. IBM went back to Gates and said, no deal... no OS, no Interpreter, we'll find it elsewhere... Gates said - We'll write an OS for you... They reverse engineered DOS... it was virtually identical to the one by the other company... Then, in the biggest pulling the wool over the eyes in corporate history... they "Licensed" their software to IBM... They didn't sell it to them and they didn't exclusively license it either....
IBM brings their PC & PCjr to market... Their prices were pretty comparable to Apples at the time (if I recall correctly around 3 to 5 thousand dollars for a PC.) They sold a few, and the market was pretty even... Maybe even Tandy had a slight edge because they were lower priced by a bit...
Then, out of the blue... someone realized that the PC could be duplicated... And better than that, people could purchase the same OS as IBM... So, the "PC Clone" entered the marketplace... an early one I remember is Franklin... Anywho... These clones were selling for half the cost of IBM's PC... They started to bark at M$... but M$ showed them they didn't buy DOS, only licensed it... thus, businesses started buying clones by the handful... because they were much cheaper than other options... M$ wrote Word & Excel around the same time we had Wordperfect and Lotus123... Then they started the whole bundling thing... and 20+ years later, we have the market of today... IBM has never been able to compete in the PC market, they tried several times... worked with M$ to develop their own "OS/2" which was actually better than DOS - and in some regards, better than Windows (it was GUI). But, the damage had been done... Mac meanwhile stumbled along, with no clones because it was all developed internally and proprietary...
Anywho... that's a bit of perspective for those who haven't heard this before. I'm sure theres a much better wikipedia article somewhere on this...
Oh, and for those who wonder about the rival OS company... it's gone as far as I know... But they did market DR-DOS in the early days of PCs... before Windows 95 came out...