I've thought about this before, and in point of fact, it is partly what made me come to feel the typical rationalist motivation to live well - there's no life after death, religion is a crutch, etc - isn't good enough a philosophy for me.
I don't want to get the most out of life by being afraid of death and trying to cram it all in before I die. Also, in time, that isn't going to be effective anymore as a motivation for atheist and rationalist to "be good and focus on the here and now". What happens when technology extends life? What happens when death isn't the end in a real way? Whether life after death happens by magic or science, the end result is the same: you need a better reason to enjoy life than worrying about or looking forward to what comes after death.
In short, I'm not concerned about consciousness after death being rationally proved because unless some specific religion's heaven is proved literally true, it doesn't upset my apple cart. This life still matters just as much. What you do for yourself and to others still matters. Experiences are unique moments in time and space. They never happen again regardless of how long you live.