It happens all the time on Steam and physical retail. Especially when the game is critically panned or is old enough that it's not selling at the original price anymore.
Pretty funny to see the big budget "AAAA" games going from $70 to $5 in just a few months, while seeing an independent game like RimWorld never go on sale and have multiple DLCs that aren't much cheaper than the base game because the former loses interest hella fast, while the latter seems to keep gaining popularity.