How much does it cost Google Search to support an extra user on the margin? I don't really know, but I'd wager much less than $1/year - because it's very implausible that the extra ad revenue it gets today from an extra user is more than that.
(The world's poorest people are a really bad target audience for ads - they have very little discretionary income!)
Meanwhile, the cost of Internet access for the poorest people is at least an order of magnitude bigger, maybe two orders of magnitude (since the cost to Google probably is much less than $1). Also, poor people's main or only Internet access is often via smartphones, and mobile data costs much more per GB than landline ISPs.
On the margin, some people who can afford Internet access today would not be able to also afford (as many) paid services. I'm willing to pay this price, in exchange for everyone who could afford access and services (including most of the poor people who can do so now) getting much better and more varied service and much less surveillance. Also, a paid model would enable people who publish blogs and other sites, and various services.
Finally, if you treat Internet or Web access and services as very important and maybe a human right, then governments should provide it or subsidize access or regulate prices. Absent that, for-profit corporations paid by users would be much better than the same corporations paid by advertisers.