I have a masters degree in predictive analytics. If people in this field are dedicating to this full-time and are allowed to have bots, you should stay far away (unless you are just doing it for entertainment). Sure you can get some wins, but long run you will lose.
It's very easy to play with a positive expectation and make a small amount of money. (Only play in freerolls that offer real-money prizes. A mathematically proven +EV, can't-lose strategy.)
It's very difficult to average a yearly income from DFS sufficient to support yourself. (Although I personally know a number of people who do.) To make, say, $50,000 a year on average, you have to enter a
lot of contests and bet a
lot of money. That necessarily means entering a lot of contests at FanDuel and DraftKings, because that's where most of the action is. And that makes winning difficult because (a) all the
other people trying to make a living at DFS are also playing there, and (b) overlays are difficult to find there.
But in between those two extremes, there is a lot of room.
I really don't think it's all that difficult for a small-time hobbyist to come out ahead. There's a lot of good information in the
Cracking FanDuel and
Cracking DraftKings books, but the most important advice for someone trying to earn a few hundred bucks a year playing DFS as a hobby isn't in there. The most important advice for that person, IMO, is to
chase deposit bonuses and (especially) overlays at the smaller sites. There are a lot of overlays at the smaller sites, at least for now. If the
average person plays only overlays, he will have a positive expectation. And it's not that hard to be above average at the smaller sites because many of the pros don't play there. There's not enough money at, say, FantasyScore to make it worth their time. When you're trying to enter $30,000 worth of contests in a given week, why go to a smaller site where, even if you enter every contest available, that's only like $1,000 or whatever? It takes just as much effort to generate a good set of FantasyScore lineups as it does to generate a good set of FanDuel lineups, but you can't wager very much on your FantasyScore lineups. (Some pros do enter every contest at every site, but I know some who stick mainly to FD and DK and just a few others like FantasyAces.) Not only are there fewer pros at the smaller sites, but the non-pros tend to enter weaker lineup there than at FD and DK because it's harder to find good publicly available lineup-optimization tools and stuff for them.
All of that may change within the next few years, but right now I'd compare DFS 2015 to Online Poker 2004 or so. It's just not that hard to beat the small-stakes games (especially at the smaller sites).