It would seem that this is wholly objective. You would have to base the thought of only three hit albums on the commercial viability of a set of songs or albums and not the quality of the actual music. When you read interviews with musicians, most will say that they strongly believed in most every track they put down. So the 'hits' are determined by the marketplace and the marketplace is constantly shifting. Tastes change, fads come and go...etc.
In other words, it's really the quality of the music AND WHEN it hits the market.

For many artists, creativity is an ebb and flow situation.

Or not. What do I know.