By comparison my parents are rudimentary users of technology, and thus their switching costs are low. As long as there is Firefox / Chrome they're ok. Some Chinese sites still depend on ActiveX but they've been replaced with Flash for the most part.
If there was, the usage of Linux would double within days.
The main issue is that there is no drop in replacement for Excel. There are spreadsheets that do calculations, statistics, scripts, etc... better, but there aren't any that can perfectly replicate Excel and perfectly read XLSX files right now...
Excel is really stupid fast. There are old stories of the Excel team at Microsoft being the most performance-obsessed group around. Excel really is a very great product. Can you demonstrate equivalent performance with Gnumeric?
If you're really performance obsessed, a spreadsheet isn't really the best solution anyway...
I agree with this, but tell that to the millions of non-programmers the world over (including almost exclusive use in the finance sector) who use spreadsheets for, well, programming.
I have heard it's not unusual for huge spreadsheets that take upwards of 15 minutes just to regenerate all the calculations and VBA macros it contains. Yes, this is horrible, but it's absolutely ubiquitous and so performance does matter. VBA support also matters for backwards compatibility with these monolithic, battle-tested behemoth spreadsheets. Python support is a great extra, but drop-in VBA support is the feature Gnumeric needs to find widespread use.
I can't fathom what you mean by "more accurate". Accuracy is binary. Are you saying Excel is inaccurate?
There's a large difference, unfortunately, but it's the edge cases that the difference lies in. Some professions rely on those edge cases exclusively however.
BUT, having said that,I think there are tons of users that could use Calc for their basic calculations (I worked in a couple of banks and I think probably just 5-10% of users used it as "powerusers" and I suspect less than half of them used functions/code that have no equivalent in Calc)
In fact, my personal opinion is that Libreoffice should abandon PPT and Word - both with adequate online equivalents - and go all out only on Excel.
There is simply no equivalent for Excel on Linux or Mac.
Photoshop + Excel on Linux would be it's killer applications.