Like all art, fonts are rarely completed and merely published. Hinting especially seems like a fine art that is never done, there's always more things to hint, and more hints to tweak towards perfection of the typographic art.

Some of my favorite fonts have regular releases. As with most art, software enables a more regular release cadence than past such systems. (Such as the days when font foundry was literal and fonts were published to metal and distributed in giant physical cases.)