I agree that many of the transactions on the IAB Standard Terms and ISDA Master Agreement are automated and don't involve negotiations. There are, however, also higher dollar value ad buys and derivative transactions that use those standard agreements and do involve negotiation.
I had a helpful conversation with an attorney who was previously at Facebook about this. They use the same basic addendum to the IAB Standard Terms for most of their ad sales, and they sometimes negotiate it with large customers.
We see a similar pattern among our users, where their lower dollar, high volume transactions don't involve negotiation, but their bigger deals do.
We don't yet have the same distribution as the IAB or ISDA, but our goal is that over time more and more companies will be able to focus just on the variables in the cover page of our standard agreements because their team has already reviewed our standard terms.