This "popular film" angle is never stated, but Rice sure as hell milks it, and for the most part it's clever and funny. The citizens of Purilia all behave according to their caste (hero, vamp, villain, virgin, or mother). The businessmen do a vague sort of work which is never explained. Farmers live on tiny plots of land, always inches from being foreclosed by a dastardly landlord. Prisoners who are sentenced to death are always saved at the very last minute.
In part seven, after speculating that high-caste Purilians rarely get diseases because their "susceptibility to wounds, bruises, contusions, fractures, and swoonings" has caused immunity, and revealing that low-caste Purilians who suffer disease (influenza, delirium tremens, gout, parasites, and "maladies of the teeth") are always subjects of mirth, the narrator describes an upper-caste malady which IS taken seriously:
Chief among these are heart-failure and apoplexy, both of which are deemed highly respectable and worthy of the expenditure of a good deal of emotion. The symptoms of these twho ailments are almost identical. The victim opens and closes his mouth several times in rapid succession, rolls his eyes, and then slumps heavily either upon the floor or into a chair. If the attack is particularly acute, he dislodges a vase in his fall, or else clutches at a tablecloth, with a resultant breakage of crockery.
This is typical of the incredibly detailed descriptions in "A Voyage to Purilia." It's simultaneously a fun adventure, a vicious satire, and a checklist of hundreds of film tropes. It's also an indication that not much has changed in Hollywood during the last eighty years. If you have a copy of the New Yorker DVDs lying around, I recommend you go back to the fall of 1929 and start reading.