> No consent. No opt-out.
Do you understand what licensing is? That's one of the underlying aspects that's important with software and why you can't treat it like other things you buy. I'd add it's also why things that adopt software-style licencing models are bad too.
A company creates a licence with terms and you agree to use the licence under those terms by using the software. The terms are difficult to change unless you have leverage. The only party other than the company is often the regulatory authority. Regulation is limited in the US at best when compared to the EU. If you are from the EU then you probably assume the US works similarly, but most Americans don't recognize issues like this one. When they do, it's hard to fight the incumbents and make something opt-in, or ban it outright.
> What's the motivation? Is it simple laziness because they don't want to deal with wetware? (the start of your first paragraph applies here too)
It's fairly simple. The motivation is making correct decisions based on the gold standards of decision-making that some people aspire to. The model is not dissimilar to clinical trials where a treatment is given to some individuals and not to others. The hope is that this form of experimentation removes bias and let's the product manager make the best decisions.
Based on this thinking it is not possible to test with just Google's employees. For many decisions, the bias will be significant, and ultimately the belief is that worse decisions will be made for users.
I'm trying to convey that in as neutral way as possible. I think this can be a useful technique, but I think that there is little discipline and accountability in the wider software world compared to medicine. You have PMs who'll routinely just run an A/B test longer to collect more data (that's better, right?), but invalidate their results, just to please management.
If anyone is going to implement this approach then I'd trust Google to implement it effectively to meet their needs. They do it on a large scale across their products and have many layers of people to ensure it's effectively meeting their needs. As stated in the previous paragraph, this doesn't mean that other people do it right, or that everyone in Google does it right every time. I'm sure they've had a fair share of failed experiments.