How does a data provider prevent someone from copying the data from their S3 bucket into a new one, then cancelling the subscription and owning the data forever?
1) It's a continually updated file, so if you didn't subscribe you wouldn't get new data weekly/monthly. Likely the subscription aligns with the data refreshes for most products.
2) It's a one-time fee with a hefty cost attached (I saw some healthcare data sets that were $100K+). You are paying for that in its entirely and just have data rights to it.
Think of the price for data on the prices of stocks. If you want to know what AAPL traded at one month ago, that's free, if you want to know what it traded at 15min ago, that's $25k, and if you want a feed which shows the actual bids and offers, that will run you $2-15mm + infrastructure.