It always seems that artists are the only people that want and even expect to profit for a lifetime from any work done. A writer writes one book, a singer writes one song, and so on. These can be sold millions of times, and the authors reap rewards their entire lives if the products stay popular.
I for one, who writes computer software (which is also creating / writing stuff), has to keep working and working, as in a matter of 1-3 years, nobody will want the current program, or current website system anymore. Maybe it won't even work on a new system. It will need to be updated or even replaced.
Work once, profit many times over. Only artists expect this, and they always whine when it doesn't work out that way. My father, who was a construction worker, never received any royalties for each time someone walks on a path he laid down or walks trhough a door he placed.