The silly part of course is that weather balloons have a finite lifespan, primarily due to loss of lifting gas as the balloon undergoes thermal cycles of expansion and contraction. Superpressure balloons suffer less from this but weeks or months aloft is still a significant achievement.
It’s been suggested that microscopic glass hollow spheres filled with dry nitrogen could behave as high-altitude aerosols with persistence times in the decades. But that would be a geoengineering feat no one is brave enough to try.