This is the crucial part, there is no reason to believe this is happening. There is not a 'glut' of expensive things as many are forced to buy the expensive alternative when their preferred choice is gone, and regular consumers of the premium brands still buy them. They just sell out less fast.
The economy is 75% of what it was 3 weeks ago. Numerous industries have laid of 50%+ of their laborers.
I’m going to wager there is less demand for premium products.
Perhaps we are each talking too generally and need a bit more specificity. If we're talking about premium products in the sense of iPhones, new cars, video games and other kinds of irregular purchases like that then I expect you're right at least in the short term. But the relevant point of discussion here is what you tend to need from a supermarket in day-to-day household consumables and their respective economy/premium products which contribute to a household's regular expenditures. In the household consumables case, the premium products are definitely still selling.
This is the crucial part, there is no reason to believe this is happening. There is not a 'glut' of expensive things as many are forced to buy the expensive alternative when their preferred choice is gone, and regular consumers of the premium brands still buy them. They just sell out less fast.