Google created android - the most popular OS. Sure maybe samsung or nokia would be used instead but definitely the helped expend ad business with android. Same like Meta/ByteDance expanded Ad business with Intagram/Tiktok. Even if ad spending grew 1.6% per year it's not sure if it grew as much if android didn't exist. Also need to take into account probably reduced cost of advertising - this product just got cheaper. That the ad market grew 50% in 25 years doesn't mean we have only 50% ads served same like 50% grow (in $) in smartphone market doesn't have to mean you have only 50% more smartphones if they got cheaper.