It could be argued that there is a finite set of contributor energy, any action by a contributor uses energy, and there is a non-empty set of people who make both on-topic and off-topic contributions. If you perceive value as on-topic activity, then OffTopicPages? cost you the value that would have been added by contributors using their energy to make on-topic, rather than off-topic, contributions.
Any particular contributor has a finite amount of energy/time/mood to dedicate to wiki. We are not immortal, you know? The more time I contribute to OffTopic pages the less time I have for OnTopic pages.
I'll try to resume a case analysis:
ZeroSumWiki is a mischaracterization. We're not saying that the amount of energy wasted on OffTopic subtracts exactly the same amount of energy from OnTopic pages. But it subtracts something substantial.
But,
Cases 4-6 suggest just the opposite: people contributing in a free-spirited and welcoming millieu, as wiki was in its first few years, generate a lot more OnTopic content than people getting slapped with HarshEditorship every time they try to say anything. It's like MicroManagement.
But still, cases 4-6 are a wash. For example, your claim that an OffTopic subject gave rise to this one is dubious. The seeds were already contributed and you weren't paying attention, that's all.
Nor there was any GoldenAge? in wiki history for which you seem to suffer such a nostalgia. Maybe the first wiki years were an uncritical glorification of objects (objects a la Smalltalk only, mind you), patterns, and XP, among a community that was as diverse as a village in Wyoming, but certainly having seen the evidence (there are still pages unchanged from that era) I feel many people will have a strong diagreement that the way forward is by moving back.
Yep people here can complain of HarshEditorship when they are called to task to face up to their BurdenOfProof or reminded about InFavorOfDissertation, or something about CriticalSpirit. When they slap together a bunch of rants on SensitiveOffTopic at a level that would not get them published in the high-school paper, the easy way out is to whine about HarshEditorship and not to see the problem where they were. But does Wiki suffer from HarshEditorship for real ? Looking for some OnTopic example I picked StoredProceduresAreEvil which is a dead and gone page (good riddance), no doubt that the guy who originated it has reason to complain that his view is not reflected. But if we are to take ouselves seriously the fact that pages with conclusion that are simply unsound from a technical point of view, are gone is progress. Some folks are more loving of their strongly held prejudices rather than objective evidence, so there can always be the case of somebody complaining of HarshEditorship. All views are not created equal. Wiki can survive though rather than succom to irreducible conflict, because people by and large are reasonable and can recognize what is an untenable or undefendable position or where there's room for reasonable people to have differences of opinion.
On OffTopic pages the two chief complainers to suffer from HarshEditorship? are RA and RK. Go figure. Do we have a problem though? I fail to see the evidence that we have.
Where I do know that we have a problem (testifying to that from my own experience as well as from a few email exchanges with other contributors), is in time and energy dedicated to OnTopic subjects. And again from direct evidence hosting SensitiveOffTopic discussion on this wiki is sure not to help. So we need to pick and choose whether the case 1 above is more important than cases 4-6. My bet is on case 1. I think case 2 and 3 are virtually non-existent (I put them more as a hypothesis). Wait a second, there's one RA that seems to fit in those patterns, but unfortunately for all the time he has on his hands his positive contribution to OnTopic has gone unnoticed.
It's just like any another economical decision: a question of managing limited resources. The resources are: the attention and the goodwill of readers, the (mental) energy and the goodwill of contributors, gnomes, Ward himself, etc.
But,
Economics is not a ZeroSumGame either. If it were, money could never be created. Nor value. A NoFunWorkEthic may hold this to be a good thing ...
But again
The fact that economic is not a ZeroSumGame (which is acknowledge) does not mean that the society can invest resources on anything (lime making another 10000 nuclear warheads for example).