In reply to Sarah Gooding.

Thanks Sarah,

Though I'm not sure this reflects what I was saying:

many of these top-selling themes offer accompanying plugins that are only compatible with that specific theme, a desperately myopic development practice rampant among Themeforest products that locks users into that theme/plugin package

The screenshots I gave above show that the accompanying plugin *is* compatible with other themes. There is virtually no difference in the content between the original theme and Twenty Twelve.

And far from being "a desperately myopic development practice", putting functionality into plugins instead of themes is actually considered best practice.