An acceptable balance between privacy, security, advertising and so forth
And there's the rub: there isn't one.
There is no way that any person with any understanding of the issues will ever accept any compromise on any of these points. Eroding privacy and security for the mindless drivel of advertising is never acceptable, under any circumstance.
Problem is, Joe Public doesn't know the issues. He's happy to run a browser that lets external parties log his browsing activities, that pops up down and sideways with advertising, that holds records of his activities which are accessible to other external parties. He runs operating systems that allow the automatic installation of programs designed to do either direct harm to him, or which allow the remote control of his computer by unfriendly parties. He visits sites which have themselves been polluted by unfriendly parties, collecting viruses and trojans along the way. He installs software and updates without thinking, because that's what you do, and doesn't really care about the other stuff they install on the fly. He answers yes to 'are you sure' because he has no way of deciding any better. If he's smarter, he accepts the reduction in speed and utility caused by necessary anti-virus programs (but he still doesn't really know what a virus is).
And none of this can be cured. You can't expect Joe Public to understand the whys and wherefores of computer operation any more than you can expect him to understand how an engine works, just because he can drive. Computer systems are an order of magnitude more complex than any other single object with which we deal on an everyday basis, but we expect them to be simple to use and infallible.
Even for the experts, we can't trust a shiny new out of the box computer: for example, is there something on the hard drive controller logic that's lying to us? I don't see an easy way to avoid that, because everything reads the first few blocks of the disc to get started and there's no guarantee that what is on the disc is what is delivered to you. Worse, is there something in the BIOS, something that sits there watching for input on bottom level ports - keyboard, mouse, the disk interfaces and so on? We'd never know...
The whole issue is one of trust, and at the moment, there just isn't any. Even products which you may have trusted for years (and incidentally been told that you *must* upgrade regularly, probably best to leave the automatic upgrade on, eh?) are sold to other companies who have their own idea about how to monetise their new acquisition and start adding little bits here and there.
There is a need for a guaranteed clean installation: bios, hardware, operating system. You'd still have to take things on trust, of course, but you'd reduce the threat surface immeasurably by simply requiring, as a legal requirement, that any computing product be supplied with a clean operating system with no third party addenda. No trial run software, no useful browser bars, no free-for-a-month. Nothing. Note that this need not be part of the out-of-the-box build (except for the hardware); it need only be available when the box is opened on a physical media which can be used as often as necessary.
Someone pointed out upthread that people will complain that they are paying for less. They are mistaken; they are paying for security - even if they don't realise it.
It's time people realised that there are other ways of funding things than endless chains of advertisers' clickbait. The bottom-feeding scum that are advertisers need to learn that their endless attempts to steal our most limited resource - time - are not acceptable. And perhaps get an honest job.