I really don't think its that simple. There's a pricing problem with SaaS products like Tinder which suggests that more people will pay if it is cheaper. And with Tinder Plus, they offer literally nothing different that would cost Tinder much more money; it just allows users to use the app more.

The problem with $20/mo is that its entering exploitation territory. Like a porn site subscription, it exploits chemical and physical addictions intrinsic to humans to derive revenue. You can say the same thing about, say, any addictive service (like Netflix) and you wouldn't be wrong. But at least Netflix prices at cost, not "value", and Tinder is literally playing with a biological drive and interpersonal relationships, not a simple dopamine addiction.