There are alernatives...
As I've mentioned before, Apple's "walled garden" is a selling point for many, who have been burned by Android's lack of consistency or security, or Microsoft's utter lack of support. These customer's could choose an alternate platform, one that does not abide by Apple's rules and get, more or less the same apps. When my mother bought her iPhone 6, I told her that she could only get apps and what not from Apple (not that she uses many, beyond a default installation), and she said, basically, "Great! Only one website to visit!" She had started her smartphone odyssey with Windows Phone via Nokia (on my naive recommendation that MS would support it, since MS seemed to have a hard-on for mobile/desktop fusion at the time, and Mom owned a Windows 8 laptop), then moved to an Android Galaxy 4s (until she heard in the news that it could catch fire), and finally bought an iPhone 6. If my mother, ignorant of technology and business practices as she is, chose an iPhone, then if someone, apparently more savvy on both business and tech as the plaintiffs are also "chose" an iPhone than there is something rather suspicious about spending $700USD on a phone for some people... Simply, I smell a rat, and a multi-million dollar payout for 3 lawyers for a month's worth of work (I'm not counting the paralegals, assistants, secretaries, ect, who pretty much never see the fruits of multi-million dollar settlements/judgements, and who actually do the bulk of the work.
As the article implies, it might be different if the developer were the one bringing the suit, but even then I would have a hard time swallowing the argument. Apple has a minority of the smartphone segment. And they make no secret to developers or customers what the rules are. Developers know what they're getting into when they bed with Apple. They can choose Android, or (HA!) even Microsoft. If they don't like Apples' terms, then they can move to a different platform, one that is more popular, and possibly, has higher margins.
It would be no different than GM being sued because you can't put a cheaper Kia engine in your Cadillac, or Nintendo being sued because You can't install your Steam copy of Final Fantasy VII on your Switch. Are people going to start suing GM because they can't install a $500 Sedona engine in their STS and keep the warranty? If they do, are they going to sue GM, or Kia for that matter, when it doesn't work right? Where does it end, when you are given a choice? People are not forced to buy into Apple's ecosystem, or Microsoft's abandoned planet, when Android and it's multitude of vendors are in play, just as they're not forced to buy a Caddy, and can instead buy a sensible Camry.
I'm not currently fond of Apple, though I have been in the past, but this is obviously just digging for gold, and hoping to strike it rich for a couple lawyers, and as an Apple consumer, I knew what I was getting in to. Indeed, I think that the entire concept of class-action lawsuits should be re-thought. It never "benefits" the supposedly injured and only serves to enrich a couple lawyers, and maybe their personal assistants. When Yahoo, Target, and so on (which I had consumer ties with) were hacked, I, as an "injured party" literally saw nothing. Lawyers saw a Christmas bonus big enough to upgrade their 20-foot boat to a 45-foot yacht.