Good question.

Most PPV cards aren't stacked.
But that's just my opinion.
And with so many wannabe promotions...it waters down the card.

Looking up that one per boxrec events, I saw one particular night, Roy Jones headlined a card. Vassily Jirov on another.

Two other names I forgot. They all had dismal undercards. What a shame there is such little collaborations amongst boxing promoters. Boxers turn promoters are no better at stacking the night with great matchup.