Egress pricing is there for another reason as well. It's meant to make it hard to move out of AWS.
If one looks at the pricing for AWS Snowball [0], their bulk data transfer device, there's no per gigabyte cost to get data into AWS, but $0.03/GB to get data out. I'm pretty sure the bits are just as heavy coming into AWS as they are coming out. :-)
I think it's also a convenient way to get rid of piracy and garbage content.
You can't host MegaFileShare on AWS because it would cost too much and AWS doesn't have to bother about useless legal discussions since your value to them as a customer is really low for this use case.
Not necessarily. When bandwidth balances you can get peering agreements, but AWS will be very server heavy. Moving data in would just improve their ratios and help them reduce their own costs, so, it makes sense to make it free.
If one looks at the pricing for AWS Snowball [0], their bulk data transfer device, there's no per gigabyte cost to get data into AWS, but $0.03/GB to get data out. I'm pretty sure the bits are just as heavy coming into AWS as they are coming out. :-)
[0] https://aws.amazon.com/snowball/pricing/