I don't think EA execs *really* believe that. Rather, it's harder to monetize a single player game that has a life of 20-60 hours, especially when it comes to microtransactions and loot boxes, then it is a multiplayer game.
You play a single player game, and then you're done. You may pick it up again at some point months or years down the road, especially if there's DLC, but most likely you'll move onto another game in the meantime. Which means that they only have the opportunity to sell you microtransactions during that brief window. But what if they made a game that you played on and off almost constantly? Like a multiplayer title? Maybe you only play it once a week for an hour or two. But it's there, and you play it for months or years. During that time, they have a constant chance to sell you loot boxes. And there's free advertising as well. That other guy is playing as darth vader. It looks like fun. You'd probably like to play as vader too. And you can, if you invest 40 hours, or divvy up the cash. But you have a job. You can't play all the time, like you could as a kid. So you pay. And now you're vader.
The modern game is not a product. It is, in itself, a storefront. A storefront you have to pay to even enter. And you know what? It works. You can say EA is greedy, and you're right, but they're not stupid. They know their lying through their teeth. And, most likely, they're not even lying to you. They're lying to investors, and casual gamers, who don't care or know better. EA has made explosive financial gains as a result of games as services. People may constantly hate them, but they make more money then anyone else anyway, so why should they care? They'd be stupid not to do this, especially since they make more money off of loot boxes then they do from actual sales of the game. Taking them out entirely is literally not an option, because in the long run they'll make more money from the loot boxes then they would have from lost sales. They know this is going to blow over. Which leaves gamers with two ways to actually hurt them. Make this a recurring PR disaster, and pressure disney to revoke the license by telling them that this hurts the brand, and legislate against loot boxes. The first is hard, because we can't let up. The contract give EA the license for several more years. The second is difficult because game companies have started pressuring the government to not legislate. But the steps have been taken to make this a long fight, and victory can only be achieved by keeping a light on this.