Developers need to assess the financial consequences of becoming involved in this eco-sphere. It's not for everyone. This is the game that we all play: some developers are eager to jump to the latest and greatest and leaving a chunk of users in the dust while other times Apple puts its foot down and some devs abandon their apps.Uh, what? I used to distribute through the app stores. Pretty much every app cost me more money than I ever made from it, thus why I stopped. The financial performance of my apps were pretty typical, from my understanding. Most developers make next to nothing. The best most people get is they get their $100 annual developer fee that Apple charges back. Divide the income over the hours they work and you find they were effectively paid $0/hour.
People who are unhappy about this are encouraged to lobby developers to update their apps. If developers are not willing to do that, perhaps it is time to consider a different app. Alternatively, people are free not to upgrade to iOS 11, if that is when this restriction will kick in.
There are always options, it's about choosing what option is best for you.