If something like that is key to an organization's workflow, competitors will probably be locked out even if they do add support, because it's like using "non-genuine parts". It will probably work 99% of the time, but it's probably less reliable than the general part, and hard to get support for the cases where it does cause problems. Reliability & consistency is often more important than cheaper upfront cost.
(I say this as a long time NeoOffice fan & paid supporter of the project.)
For example if I put 1, 2, 4, 8 and I highlight that and drag it to continue the series I get different results.
Excel gets it right and provides 16, 32, 64, etc
LibreOffice provides 2, 3, 5, 9, etc
OpenOffice doesn't do any better.
I haven't tried gnumeric in the last 10 years so I can't remember what it does but I'm not optimistic.
There are a lot of these kinds of things where Excel really has polish and the others don't and probably never will because the code to make it work right is excruciatingly boring to write.
What it'll take for LO Calc to compete with MSO is someone wanting to knock Excel off its perch and spend money on the drudge work. LO finally has decent data structures in Calc and the GPU calculation, now there's all the drudge to do to literally beat the best spreadsheet available. If you got the sort of serious spreadsheet that takes Excel 24 hours to run, and Calc ran it in 20 hours, people would pay any amount of money for such a thing.
(I think Excel is the hook, because it's the one bit of MSO that the people who sign the cheques use personally. Maybe Powerpoint too.)
As a word processor, Writer is every bit as good as MS Word, though of course slightly different. DOCX compatibility is improving noticeably every release; I haven't had any problems myself in several years.
Compatibility quirks are important to someone when they bite them, but look at Google Docs - it's hugely popular (basically for non-sucky email) even though its word processor and spreadsheet are terrible. We use GApps in the day job and I keep LO to hand for when I need something not terrible. Or that offers non-terrible DOCX rendering.
So I think what LO needs is something killer. Not sure what though.
How so? They seem extremely productive and reliable for the org I volunteer at as treasurer.
I've never seen a financial report with an incorrect addition, or hear anyone complain about the word processor.
My kids use google apps at school for things like writing essays and homework submission. Again, "just works".
What I really want is LO to read/write to Google Drive transparently, but that's still an experimental feature (though it works well in TDF builds, but only for password authentication, not for two-factor). Again, it awaits someone spending money on it.
For work we MS Office or LO for MS docs from elsewhere. LO is much better at correctly reading in MS-generated docs than Google Docs, and of course MS Office for people who spend most of their time dealing with documents from outside (not me, thankfully).
We use Google Docs for all of our internally-generated stuff, though -- the concurrent editing in particular is quite useful. We sometimes collaborate on docs, and each person can add their section at the same time. You can review someone else's work on a spreadsheet while they're doing it.
I recently went through an important (and politically complex) meeting where the CEO and I shared a Google doc for taking notes. It was awfully convenient; I could provide him constant feedback on technical issues but let him decide what to actually say, and how to say it.
I'm less happy with how Google Drive is integrated with Google Docs (not well), and I'd like to see concurrent editing in Sites, but maybe someday...
gnumeric does simply replicate the series, you get 1, 2, 4, 8, 1, 2, 4, 8, 1, etc. It does offer a tool to fill series though.
http://oeis.org/search?q=1%2C2%2C4%2C8&sort=&language=&go=Se...
They're probably not unreasonable fall-back strategies if something isn't strictly linear, but just because I understand why the programmer might have done that doesn't mean it makes sense in general.
Is there a list of these features anywhere? And are the competitors to MS Office working on them? Or are they focussed on different things? EG a spreadsheet that focuses on correctness and auditing could probably be useful.