If 80% of us pop. Carry hsv1 virus why isnt genital herpes much more common with oral sex being such a popular activity?

You're right. With the growing popularity of oral sex activity, the hsv2 virus is becoming more common. It used to be that hsv1 was oral and hsv2 was genital. It is now recognized that they are both similar viruses that can affect either site. The strain is truly irrelevant as they are both highly contagious, prone to recurrent eruptions, treated with anti-viral medications & can lead to permanent nerve damage.
Both are common. The prevalence of infection in adult us population for hsv-1 is about 60% and for hsv about 20%. There is a lot of crossover with the two types.

Related Questions

If I had hsv1 outbreak on my mouth and had oral sex with husband could I have gotten genital herpes that way?

Herpes Simplex. If you were the one with an outbreak in this scenario, the concern is that you transmit HSV to your husband, not the other way around... The chances your husband can get herpes from you due to oral sex is low, unless you have open sores in your mouth when you are performing oral sex on him. Read more...