Why do they deserve a cut?
Uber and Lyft, deliver a material service, Apple have not contributed to that in any way beyond existing as a general purpose computer manufacturer.
Take an alternative, food delivery service, you pay a monthly subscription for a set selection of fruit and veg delivered every week. The cost is made up of food cost and delivery cost... You could sign up through a website, or you could sign up through an app on Apple's app store, in the later case the only option would be to increase the price by 30%, because there is no where near 30% profit left over.
Not convinced? Ok lets go to an extreme, what about a mortgage monthly repayment app, that's essentially a subscription to your home right? Do you think Apple deserve to have almost 30% of the value of your house for the privilege of letting you use an app to pay? Does their App store really deliver that much value?
Before, it was sort of justifiable when people were trying their get rich quick schemes with flappy bird clones... because the argument from the other side was a weak "but that's my get rich quick scheme", Apple's platform and what they shove in front of users faces made a real difference to the almost pure profit of those Apps, the apps simply would not be popular without Apple... but as soon as we start talking about apps that deliver material services and other significant value it makes no sense to argue that Apple deserve even 1 penny. Apple have gone completely fucking mental with their own greed, they think they deserve a slice of the entire world.