This strategy could at least amass a huge horde of older media (which I think still constitutes the bulk of GOOD media), if combined with thrift stores, for very cheap. Probably you could profit during the buying & selling of the media.

They all have piles of audiobooks, audio cds, dvds, a blu-rays for $1-$2 each. Sometimes big boxes at yard sales for a few bucks.

They're $20-50 for complete series on dvd on Amazon right now. That's 14-35 new shows to get every year for the same price. I believe it's cheaper. This is why so many companies push subscriptions. If DVDs made them more money than they'd be pushing you to buy them.