I listened now to the last episode of Treason of Isengard and heard the angry reaction to this idea. However, I think it can fit. The kingship of Gondor is not yet established as the inheritance of the line of Elendil. Elendil's job was to overthrow Sauron, and now Aragorn finished the job. I see it as Elendil's line being able to finally die at peace. Aragorn would probably have someone else to inherit him, and it is not more sad than Frodo leaving Middle-earth childless and leaving everything to Sam.