I think this post is actually plausible. A smart game designer whose goal is retention would implement something like this. However, it probably wouldn't be a hard 0% chance for the "no" weapons for a given player. Instead they would skew the probability tables so that everyone had one or two prized guns that were very low probability - say 0.001% chance instead of the usual 0.1% chance. This would mean that some users would still get all of the guns, so the community would believe it's possible. But this would be rare and the vast majority of users would keep grinding to get there.