I'm guessing it is because adblockers don't usually work on apps, but they do work on websites.

With firefox on Android i have ublock origin, on the reddit app i don't - I'm forced to watch their ads however they feed them.

Plus, push notifications like "have you seen this post?" and "your comment got 10 upvotes!"

Even with regards to adblockers, they must be bouncing a ton of SEO traffic and eventual users to try to overcome that.

Nobody other site is so belligerent in getting you onto the app so I can’t see how it’s a net positive for them.

If you’ve ever had the misfortune of using the app you would get it. You are instantly under their control and they show you what they want to show you and what they are paid to show you. I’ve tried many times and it is always a miserable experience and a quick uninstall.

More control, more data, better tracking.

Ads are easier to block on the browser.