This is actually a big thing I learned when going to school for accounting. Any business that isn't growing is considered stagnant and will fail without new customers. So the two options are:
a) change your business somehow to bring in new customers. This can be difficult unless you're a first mover. If the market is saturated with competitors, you'll have to steal clients.
b) move into a new vertical and offer a completely different service. That's what reddit is doing. Since they're a fist mover in the API market with existing brand recognition, they're trying to control the baseline cost for the product.
The concept of eternal growth is actually a contributor to why we have recessions. Businesses grow to the point that they either have to charge crazy prices or commit fraud to keep up with market expectations - too much pressure to preform in the stock market. Then the bubble pops and companies cut their biggest cost (labor) to try and stay afloat.
This is brilliant. Instead of advertisers making sponsored posts that are ignored or trying to sneak an ad into a community, they can outright buy engagement. Utilize subliminal advertising, then advertisers buy their own "tips" (or whatever they end up being called) and they get back a portion of the money spent. There's been an uptick in those types of posts lately and reddit's just leaning into market trends. Not to mention that bots can earn real money by reposting top/all time content!