There is way more at play here. A data set is not just an email. Email is worthless and they can get it for free from Twitter, about 3 cents from any one of a dozen other social media platforms. What they're buying is a complete data set on a person along with a WTA (willingness to accept) rating. This involves a process of contacting the person with a set of targeted ads and seeing how much and how far they're willing to interact with the script. If you click the link, it's one score. If you click another link within the website, another score. If you end up purchasing the product, a higher score yet.
The average value of a person's data set along with a perfect WTA (buys everything) is worth about $250 on the average to the person who owns the data. That doesn't mean they pay $250 per person to purchase their data, that means that the data they purchased (on average) will net them a profit of $250. Of course, a miniscule percentage of the people have perfect WTAs, so those numbers drop as WTAs drop. The average complete data set along with a WTA score... which means the data miner has already done months of research on the data set... is likely worth a couple dollars.
Because these corporations know that the average profit they get from each complete data set means that each set is purchased for pennies. The money comes from the use of bots that do all the work for you.
You know how you do a google search for "best dog food" and then suddenly you get ads for Dog Chow and Nutro? Those are the bots at work determining your WTA.
It boils down to this. Even if you were able to mine 100,000 email addresses, they would be worthless. You can get email addresses anywhere. The value is in the targeted research and the complete data set of age, political leaning, browser history, primary language, vehicles owned, what kind of TV you have and what you watch on it (which, by the way, you had to accept when you bought the TV), which SiriusXM channels you listen to, what your credit score is... the works.... THAT is the data set that is worth a little money.
The big thing is, it's not just a once and done deal. People always ask... well won't they finally get info on everyone and the well will dry up? It's dynamic. Every time you log into GRM, FB, whatever, you add to your data set. You are constantly updating the websites you view, how their frequency has changed, what type of youtube videos you watch. It will never run dry because we keep giving them more data.