What Facebook hides in this statement is that the cost to consumers on average probably isn't that different. Small companies brought in enough revenue through ads, which means people clicked through the ads and made purchases, which brought revenue to the advertisers -- enough to sustain the small companies displaying the ads. Companies aren't going to keep advertising forever if it doesn't bring in more money than the cost of the ads. A subscription is a much simpler model; though, I note that people do resist subscriptions.
Part of this is likely psychology. Ads are less direct and allow small companies to monetize other companies' products for their own support. I suspect (though don't have data to directly support) that there is more manipulation of consumers to buy through the ad-based model vs. the subscription-based model. They probably buy more items they wouldn't otherwise have purchased in the ad-based model.
Finally, I'm curious what Facebook takes on every ad sold. What is their take on each ad? Their corporate net profit margin appears to be about 32% (see here), and about 99% of their revenue comes from ads (see here). In that they have expenses for developing and maintaining their various social media products, I suspect their take on each ad considering these two figures is higher than 32%. Does anyone know? A quick search didn't reveal that figure.
Note that Apple now offers smaller companies a 15% take through the App Store. Further ongoing subscriptions are a 15% take if I remember correctly (after the first year).
I suspect a subscription model might be cheaper to consumers dependent on how many extra items they're buying from ads. Facebook seems to be very motivated by profits in all of this -- they have much more to gain or lose based on how this turns out when 99% of their revenue comes from ads.
