There was no sense of urgency because the closest to reaching the limit aside from Berkshire is several factors away. Also, Berkshire stock has surged ~30% in the past ~6 months which is far above usual performance.

Those aspects together probably allowed it to be deprioritized until it would be closer to being necessary (a classic tale).

It is rather funny to imagine Warren Buffett sitting there mumbling about stock splits and the incompetence of it all, and how in his day, you could buy a share for however much cash you wanted to without worrying about integers and bits and code.