I think the problem here is that that is often still not that acceptable. Let's imagine a system with say, 100 million users making 25 queries a day, just to give us some contrived numbers to examine. At a 10% error rate that's 250 million mistakes a day, or 75 million if we're generous and say there's a 3% error rate. Then you have to think about your application, how easily you can detect issues, how much money you're willing to pay your ops staff (and how big you want to expand it), the cost of the mistakes themselves as well as the legal and retutational costs of having an unreliable system. Take those costs, add it to the cost to run this system (probably considerable), and you're coming up on a heuristic for figuring out if possible equates worth doing. 75 million times any dollar amount (plus 2.5 billion total queries you need to run the infrastructure for) is still a lot of capital. If each mistake costs you $0.20 (I made this number up), then maybe $5.5b a year is worth the cost? I'm not sure.
It's probable that Google is in the middle of doing this napkin math given all the embarrassing stuff we saw last week. So it's cool that we're closer to solving these really hard problems but whether they're acceptable is a more complicated question than just it used to not be possible. Maybe that math works out in your favor for your application.