Talking about billions is disingenuous, you should be talking about percentages of revenue. Ten billion _sounds_ like a lot but really isn't.
For Google, over 80% of their revenue comes from ads.
Apple's revenue is around 380 billion, 5-10 billion in ads is in the "other" category if you draw a pie chart of it... They make 30 billion just selling iPads - their worst selling product.
Apple can lose the ad category completely and they won't even notice it. If Google's ads go away because of privacy protections, the company will die.
Talking absolutes is not accurate either. Not all revenue is equal.
There is reason why NVDIA, TSLA or stocks with growth[1] potential gets the P/E multiple that their peers do not or an blue chip traditional company can only dream of. The core of Apple revenue the biggest % chunk of iPhone sales is stagnant at best falling at worst. Services is their fastest growing revenue segment and already is ~$100 B of the $380B. Ads is a key component of that, 5 years back Ads was less < $1B, that is the important part.
Also margins matter, even at Apple where there is enormous margin for hardware, gross margins for services is going to be higher, that is simple economics of any software service cost of extra user or item is marginal. The $100B is worth lot more than equivalent $100B in iPhone, iPad sales where significant chunk will go to vendors.
Executives are compensated on stock performance, stock valuation depends on expected future growth a lot. Apple's own attempts and the billions invested to get into Auto, Healthcare, or Virtual Reality are a testament to that need to find new streams of revenue.
It would be naive to assume a fast growing business unit does not get outsized influence, any middle manager in a conglomerate would know how true this is.
A Disney theme park executive doing even 5x revenue as say the Disney+ one will not get the same influence, budgets,resources or respect or career paths.
[1] Expected Growth, doesn't have to be real,when it does not materialize then market will correct as is happening to an extent with TSLA.
they generate between $5-10B on ads alone a year now and more importantly that is one their fastest growing revenue segment .
Add the context of declining revenue from iPhone sales. That revenue and its potential will have enormous influence on decision making .
The thesis that Apple doesn’t have ads business so there is no use to collect the data is dead for 5years now