I think you're talking about the businesses' motivations and I'm talking about the random EU bureaucrats that imposed the regulations. Despite how skeptical I am of most government interventions, I'd tend to assign benign intentions on the bureaucrats part here as I'd have to guess that they genuinely wanted to do something good. But like any bureaucrats sitting in their ivory towers imposing rules on others, the majority of their rules have unintended consequences, can be taken advantage of, are usually designed by committees that even when well-intentioned produce a mish-mash of inconsistent ideas, etc.
The rules are actually fairly sensible: the fact that the banners are deliberately confusing is actually illegal. The issue is that national agencies who enforce the rules (because EU rules are implemented via national laws) aren't enforcing the rules properly.
The "make it part of the browser" argument doesn't work in practice because the GDPR covers the intent and purpose of data collection/processing rather than any specific technical way of collecting or processing said data. Blocking cookies at the browser level doesn't prevent the website from using browser fingerprinting or the information you manually provided (your delivery address to make a purchase for example) in a way you didn't agree with.
I agree there is a greater chance they're more stupid than a brick than they're malicious but I wouldn't exclude the idea that internet gatekeeper like Facebook and Google are bribing them to create extra barrier for newcomers to have independent websites.
The net result of VATMOSS, GDPR and cookie banners was that a ton of small businesses decided not to bother with a website and moved to being FB only or Amazon only.
