Companies do marketing because these techniques work, not because they enjoy being evil. If you work in tech, part of your income is likely dependent on marketing, whether you think about it or not.
These techniques work... to make them money... which is the part they enjoy. The distinction between evil for money and evil for evil's sake is mostly academic.
But your main point is correct: for most of us here, the screen we view, the ISP subscription, and sure as hell this website, were all paid for in part – perhaps in _large_ part — by fleecing at scale the technically unsophisticated, who lack the faculties to evade the machines we build for companies whose hunger will persist even after it has swallowed every coin from every pocket from every destitute man on earth.
Just off the top of my head I can only think of one company that I allow to send me marketing e-mails -- I bought a ukulele over 20 years ago and they send out a couple 'newsletters' a year which IMHO is acceptable, doubly so since I haven't picked up a ukulele in over a decade.
Contrast that with my last online order that started sending out at least two a day as soon as they got their dirty paws on my e-mail address and I had to unsubscribe even though I was/am interested in the 'new releases' they were spamming my inbox with.
There's a line from Wilfred Owen's "Dulce et Decorum Est" that floors me every time.
His hanging face, like a devil's sick of sin;
As you say. They don't enjoy being evil. But they are. They know it too, and it sickens them as much as all of us.