Minor nit - See's candies is a luxury good and shouldn't affect the average customer from becoming poorer.
Healthcare, hosing, education, etc. on the other hand...
Give the actual product didn’t change, just the pricing, it actively takes money away from ordinary people and gives it to a few. Would you consider Disneyland similarly a luxury? It’s sad how expensive it’s gotten to keep Wall Street happy, meanwhile it allows for rich kids to go but not poor. Same with baseball games. Same with literally everything. Raising prices to make more profit disproportionally hurts the poor, and makes them poorer.
* Rice, Buses: 'inferior goods', because as people get richer they shift their spending to other goods.
* Bread, Cars: 'normal goods', because as people get richer they spend more on them.
* Caviar, Sports Cars: 'luxury goods', a category of normal goods where as as people get richer they spend a much larger percentage of their income on them.
See's Candy is a high-end candy brand, and I would expect it to function as a luxury good here.
But even then, I wouldn't be surprised at all if had your grandparents suddenly had 20% more money their spending on Sees would have gone up by more than 20%.
In economics, a luxury good (or upmarket good) is a good for which demand increases more than what is proportional as income rises, so that expenditures on the good become a greater proportion of overall spending. Luxury goods are in contrast to necessity goods, where demand increases proportionally less than income.
c. 1300, "sexual intercourse;" mid-14c., "lasciviousness, sinful self-indulgence;" late 14c., "sensual pleasure," from Old French luxurie "debauchery, dissoluteness, lust" (12c., Modern French luxure), from Latin luxuria "excess, extravagant living, profusion; delicacy" (source also of Spanish lujuria, Italian lussuria), from luxus "excess, extravagance; magnificence," probably a figurative use of luxus (adj.) "dislocated," which is related to luctari "wrestle, strain" (see reluctance).
That said, this etymology tends to support your position, given that at the heart of luxury is the sense of self-indulgence. Which would seem to apply to the non-essential nature of See's Candies.
Regardless, I wasn't arguing for or against your view, only providing what seems to be an interesting datapoint.
Cheers.