The market is much much larger for individual items vs. Selling an entire lot.
The lot will be undercut to allow room for profit at /near " market "value. Individual items will get closer to market value because theres no hit to take from a broker.
Like the old saying you only get out of something what you put into it.
I see "lots" that sit unsold with great items, that would move more quickly if sold individually.
To each their own however, its none of my buisness how someone chooses to unload their collection and everyones circumstances are different.