So, there's lot to mull over in that story. 

For starters, there's the obscenity of the wealthy's problems being caused by simply having too much money.  Take that a step further and the situation portrayed may more accurately – and profitably – be considered as a systemic problem:  The Riches are plainly simple buffoons who don't know where their money is coming from and don't know what to do with it beyond storing it away.  It is the tendency of money in a capitalist society to follow money and so accumulate in unmanageable concentrations that is shown to be the problem here.  And then there's the lurid Freudian undertones of spurting cash and throbbing phallic symbols in need of release all linked to this excess of wealth.  And what to make of the closing, concretization of the titular metaphor?  On the one hand it could perhaps be seen as the alchemical phantasm of a perpetual motion machine, but that would be cheating ourselves of its more laden, contemporary meanings:  This comic was created in the wake of the "Oil Crisis" in which the global intersections of wealth and oil (and, of course, power - in both senses on display here) were linked more clearly in the public mind.  Thus the title of this tale highlights the historical moment when the mechanical sense of power – as in its generation and use to power modern civilization and its attendant machines, including, of course, automobiles – rose to join the traditional senses of the temporal and political that had largely attached to the phrase "money is power" previously. 

Add it all up and it comes to... what exactly? 

Certainly this story tells us something about capitalism, the global economy and, particularly, American society's (mal)adaptive responses to the contemporary exigencies precipitated by the rise of global capitalism.

So, perhaps you would like to go back and read it again with this in mind and see if you can figure it out.

Or, just move on...