plenty of people from other countries visit - 1B people out of 8B speak English, and also this is only for the Fun stream, whereas other streams can be created by users in new languages
I mean that no one pays in order to remove ads or remove "trackers". Maybe a couple people do, but the world population as a whole doesn't care whatsoever. This is the same reason that advertising still exists. In theory if all humans were capable and intelligent, click-based advertising would not even exist, and there would be much less money in it. Unfortunately, most humans would rather save their $5 (or even $1) rather than avoid ads, and most humans are also dumb enough to click ads despite independent research being a better decision 100% of the time. As a result, most content-based websites on the internet are forced to monetize primarily by advertising rather than higher quality payment-based models.
Despite that, we value the ability to always pay to disable ads, even if only a few people utilize it, because internet ads are just a shitty aspect of life.
Most people subscribe to Pro because they want the meme/gif features.