Someone running a r(ating)-aas business might have 1000 accounts and order 1 cd per customer per account. Limiting per account forces them to make more accounts, which means more phone #s, more cc numbers, more cost, and makes them easier to spot.
Then again their best recommendations to me are extremely simplistic "you bought a washing machine, maybe you want a washing machine?" attempts, so I guess not.
Or they just don't care that much because that costs money and this is just easier and cheaper.
Even if 99% of washing machine buyers won't be in the market for a new one, that's probably still a better ratio than you'd get from advertising to random people who haven't bought one lately.
If, after 30 years of putting our best minds on the problem, this is the best we can do, then the entire advertising industry deserves to be burnt to the ground for making zero progress while wasting untold riches
These are used Audio CDs. You're lucky if Amazon has one 3rd party seller with a copy to buy. There sure as hell aren't thousands available!