More inventory means more chances to sell something to an advertiser. That is why they go to such great lengths to build massive data centers with gigantic digi

More inventory means more chances to sell something to an advertiser. That is why they go to such great lengths to build massive data centers with gigantic digital brains to figure out how to optimize session depth, impressions/user, watch time, etc. Buyers are not able to pay beyond their profit margin, so increased rates just means they cut budget and look somewhere else.