How would this work in more "classical" software where I only get presented with the EULA after purchasing it, downloading it, and launching the installer? Mone

How would this work in more "classical" software where I only get presented with the EULA after purchasing it, downloading it, and launching the installer? Money was already exchanged. How could any contract made after that be enforceable? Wouldn't that mean you're obligated to retroactively give away rights you aquired through the purchase minutes before?