That is a complete nonsense statement.  The whole point of 'the tragedy of the commons' is that indeed 'the commons' work find as an economic model (and in other ways) when there are abundant resources.  Saying that 'Commons still exist and work fine' makes zero sense unless you are specific about what instance you are pointing to.

The principle applied to Bitcoin mining casts 'the commons' as the Bitcoin system generally with the underlying assumption (arguably incorrect) that centralization is bad.  Abundance would be when there is no threat of centralization.  In that instance maximizing personal gain can be done without threatening the system because it doesn't matter what pool he associates with.  In the more classic scenario it would be the same thing as the sheep herder growing his flock to the maximum number he can handle without worrying about ruining the graze on the commons since there is so much of it.

Yes, it is true that 'the Commons still exist and still work fine' in Mongolia.  They've ceased to exist and work fine in many other places where they once thrived.

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It would be interesting to note when the first time Satoshi seemed to be aware of the concept of mining pools.  I suspect that it may have been one of the things that he (or they) really didn't anticipate very clearly in formulating the various constructs which were to influence the ecosystem.  One of the impressively few things I might add.