You've got to think beyond the computer. Most big companies pay per ad view, not per click. Per click is for the low-end advertisers. Per action is for bottom-feeders.
Think about billboards, TV, radio, and magazines. Can't click on any of them, yet hundreds of billions of dollars are spent on them every year because repeating the brand, logo, visual, or message works. There's a reason McDonald's and Coca-Cola advertise heavily. It works.
I strongly disagree about your CPM/PPC/CPA categorization.
I work on conversion focused ad campaigns, so YMMV. For conversions, obviously CPA and PPC are superior. I do agree that CPA can be bottom feeders, but PPC is probably the bread and butter of most people I know.
I would suggest that most big companies are paying their agencies, who like pay per view because they can spend more without direct accountability like Return on Ad Spend (ROAS). Their job is easier without having to prove their efforts work.
Grain of salt and all. I'm also a guy who has yet to see proof that a branding campaign has value. (It may lift sales, but is it the most effective use of those dollars? Doubtful.)
Why is CPA for bottom feeders. What do you mean by that? Seems like the perfect way to optimize the funnel if you know exactly what you're after (an "acquisition").
Think about billboards, TV, radio, and magazines. Can't click on any of them, yet hundreds of billions of dollars are spent on them every year because repeating the brand, logo, visual, or message works. There's a reason McDonald's and Coca-Cola advertise heavily. It works.