Consider this: modern capitalism was pretty much inconceivable to people living in the feudal era. In the same way, it is possible that the system we need is inconceivable to us at the moment. Critiquing capitalism and advocating for a move away from it is still useful.

There are plenty of things that haven't been tried aside from small-scale examples:

• An economy based on worker cooperatives
• Universal Basic Income
• Universal Basic Capital
• 'Library economics' or 'Library Socialism'