It seems like being nearsighted for much of your life due to elongated eyes would make it easier in general to focus on near objects rather than far since the lens would not have to change much. Since in old age we lose the ability to focus close images due to a hardening of the lens over time, wouldn't having eyes shaped more for near images be helpful in maintaining the ability to see close up, and thus nearsighted, or myopic people, would be less likely to develop farsightedness, or hyperopia, with age? It seems then that nearsightedness is more of an adaptation that occurs at a young age, so that these people can work up close for longer periods of time both in the the short term(studying) and long term(age). I'd love to hear if any research has been done on this subject, and any other input you have.
It is generally understood that we tend to become hyperopic as we age (reference). As to whether this aids in decreasing myopia is stated as marginal in papers. One paper titled "Is there a hyperopic shift in myopic eyes during the presbyopic years?" states that
In a second study titled "Age-Related Decreases in the Prevalence of Myopia: Longitudinal Change or Cohort Effect?", it was found that there is a decline in the prevalence of myopia in older adults.
Some people in personal experiences have stated that their myopia has decreased (reference) while others found themselves wearing bifocals (reference). In closing, I would say that this is something that your eye doctor may be able to predict better but it is not a given that your myopia would decrease. It may or may not be so with many factors like your eye shape coming into play.