Only you can judge whether maintaining the relationship with your family is important to you. It's certainly not required.

Your family is giving you a good illustration of how they will consider their relationship with you moving forward. If this is tolerable to you, then continue to do what you are doing. If it is not tolerable, then change your approach.

Perhaps it is more tolerable to you to offer them a one-time "grant" that is less than the entire "package" they are asking for. Remember that the decision you make today is for today's circumstance only. It does not bind you for the future. If they use that as a springboard to ask for more in the future, you can always say "no" at that time.

NAH, I guess. I know what my own stance would be within my family, but it is based on our very specific familial structure, so I would never consider recommending it to someone else.

I think the important thing is to realize that choices have consequences. You know yourself and your family best. How do you wish to continue the connection with them, at this point in time? Do you think there is enough mutual love, respect, and support to continue being a part of each other's lives, or are you convinced, at this point, that they are only exploiting your financial advantages?