It is just that until you explain HOW you organize this without ownership, it is impossible to determine how such a system without ownership compares to the current one.

To a a close approximation, the new system looks just like the old system, just without the paychecks. Assuming that workers know their value (big assumption), then the question becomes "to create the most Xyriking, should I do my job or change to a job producing Xyrikes?"

Caviar producers should change jobs; grain producers should not; salt producers should determine what exactly is meant by "temporarily" before making a decision.

Taking the hypothetical as it is given, I think it is fair to assume that no one will quit their job simply because it is unpleasant or because someone else could do it -- those don't really count as working together (or "pooling resources ... without worrying").

Human resources include skills like planning, logistics, common sense, and health and safety. Of course, it is possible that good planning skills are so limited that they must be devoted primarily to producing Xyrikes, and not keeping people healthy.