You might want to actually speak to people who have no children and plan on having no children. What you say is largely not remotely true. In fact, many of them choose not to have children because they are concerned about the future.

I don't have kids,don't want kids and have no plan of having kids,but I have family and friends with young kids and I very much don't want them to live in a nightmare environmental disaster. So I think I do have a stake in the future since it effects everyone I love and care about.

Some of us value humanity itself, marvel at our technological achievements and hope that one day our species will stop it's petty infighting and venture out to the stars.

Don't tell me I have no stake in the future, I am way more concerned with it that any of my childbearing friends or family.