You’re operating under multiple misconceptions. Developers set the terms and conditions for their applications and free trials, not Apple. Apple has to enforce the developers terms and conditions. The cost of an app is not based on the time you use it or don’t use it. No one can monitor the time you used it, or if it’s even installed on your iPhone. You are charged per the terms and conditions for the free trials. If you don’t follow the terms and conditions, that’s on you and your wallet. There is no standard of 5.99 or 10.99 and there never has been and I’ve been an iPhone user since 2007 and when the App Store was introduced in 2008.
Many app offer free trials. Generally the terms and conditions are something like a free trial of a limited period of time, often 7 days. The subscription must be cancelled at least 24 hours before the free trial ends. If you do not cancel the subscription, it automatically converts an annual subscription. When you agree to a free trial and the terms and conditions, you’re agreeing to a legal contract.
Greed isn’t even a part of it. You may rationalize your actions or lack of by throwing words like greed around, but it doesn’t make it true or valid. I’ll throw a few around. How about responsibility for your actions? You agreed to the free trial, but do you follow through by reading and understanding what you’re agreeing to? No, but that would be the responsible thing to do. How about canceling the subscription? That would avoid all this and you wouldn’t be upset. That would have been responsible. How about asking how to cancel subscription and insuring you don’t have to pay these charges in the future? That would be the responsible thing to do.