Shopper can speculate all day long, but the people who own and run this business are the ones who know the shopper demographics. It's not likely anyone is going to come on and say that their shoppers are mostly, 2 new car, nice house and >$200,000 a year incomes.
Based on 20 + years in this business, both as a shopper and a scheduler/editor, the vast majority of shoppers are older and not wealthy by any means.
A few simple examples:
A scheduler friend had an account that was changed by the client, which required shoppers to be under 50. More than 75% of her shoppers were no longer eligible to do the shops. In some areas, she no longer had any shoppers to do the shops.
Age compliance shops are notoriously hard to fill (not just the under 25 year old ones either, some go to 30 years and up).
I was the only person in the Las Vegas area who had enough credit line to make some purchases for a particular account. The credit line required was only $50,000. I'm not surprised that most shoppers couldn't do it, but NONE of them could do it.
Shopper conferences are generally held at lower end properties, since most shoppers can't afford the nicer venues. (Thinking of Crown Plaza, Embassy Suite, Greek Isles & The Flamingo in Las Vegas).
Some of these shops and audits are hard work. Thinking about doing a gas station audit in TX in August or one in Michigan in February. Heck, taking photos of a dirty bathroom in Malibu in April doesn't sound all that fun either. Perhaps a reimbursement only job for 2 tacos or $15 in groceries?
Obviously, the shopper pool includes people of all ages, races, abilities and incomes. There is still a basic demographic once you do the averages though.