Whenever a justification for phenomenal increase in price of land ( in India , in current context) and Gold ( globally) is asked for, a reason given is " these resources are limited " and " God does not make it anymore". So, the prices will always keep going up.
At the outset, this looks like a very compelling argument. But , if you think more deeply all products or many services are also dependent on natural resources for that matter . Also most of these natural resources are not available for ever example, clean potable water, mineral ores, oil, forests, etc and so on.
Nothing is really non depletable unless the man kind use them prudently.
So, the argument of limited availability can be extended to man made products also which the listed companies sell ( as they are dependent on some natural resource or the other which God doesn't make anymore).
Buying something as an investment only based on the above argument doesn't sound logical.