This is it. For nearly 15 years money was basically free for tech companies. Banks don't pay anything, bonds don't pay anything, the stock market is overheated and investors are still looking for return. So if your tech company was already public you could borrow in the form of bank loans or bonds for dirt cheap and if it was still privately held you can get money from individual and corporate investors.

Now that the free money era is over a lot of companies have had to finally think about making a profit so that they can keep the lights on. This is why there have been tens of thousands laid off in the tech sector in the last year or so.

As far as Reddit goes I have no idea what they've been thinking. It seems like they've been spending money developing features nobody wants or needs: locally hosted images and video which have to cost a fortune, live chat, and NFTs, to name a few. They've got the ~20th most popular website in the world with millions of daily active users and they can't figure out how to make it profitable?

The API the third party applications used doesn't serve ads. All they had to do for a bump in revenue is to insert ads and require third party applications to display them or risk losing their API access. Users would grumble but it's a pretty reasonable ask. The fact that they didn't do this demonstrates to me that they don't think the money is in serving ads, they think it's in data mining and they can only get the data they want from the official app.