Earlier quoted context omitted.
If you program a browser to consent for you that is no different to consenting yourself. Just as writing and running an install script with --accept-tos is valid.
That's not informed consent but if you decide to accept everything without reading anything, it's your right to do it. You won't be able to complain in case of "surprises". So yes, a browser could come with an "Accept all" setting, probably disabled by default, but which browser vendor is going to go through the trouble of implementing that, proposing an API and above all getting every Privacy Agency of the world to…
A court would look at this and a person who mindlessly clicked "accept all" on every website as equivalent.
Browsers could propose an API for this functionality and no doubt some websites would implement it. They havent but they could.
Whether there's any point is another question. Websites would probably rather use dark patterns to get us to click accept all, so any API that went beyond accept all and allowed a standardized user policy on data collection would have a limited uptake.