Theories On Why Finasteride Is Less Effective For Hairline?

[dralex]

I know we don't really have any hard science on this, but what are your theories for why finasteride seems to be less effective on the hairline than the crown. Do you think its because the hairline is more susceptible to DHT, and therefore finasteride isn't potent enough? Is it because the hairline recession happens first and people don't start finasteride fast enough to prevent the recession (already miniaturization there)? Do you think loss on the hairline is actually caused by testosterone or other hormones, and therefore finasteride is less effective there?

Curious on everyone's thoughts. If you have any articles/studies to back it up as well please post.