He addressed it in the post, he's not really interested in that kind of work.
Technically possible, but not really feasible due to the way Reddit is set up and people who signed up for the app agreed to. It would be a gigantic mess, and I reckon he's not interested in creating a new social platform/link aggregate which is why he would rather refund the ~$250k.
You should read the post, he addresses this in it.
This never struck me as a realistic option. The Apollo user base is orders of magnitude less than Reddit, and, even though Apollo is an incredible iOS app, the primary benefit of a large social network like Reddit is the social network.
Might be a pretty big legal argument if he just copied Reddit backend functionality. Would probably have to redesign the front end from the ground up as well to make it clear it’s not just a rip off.
I don’t think cloning products is illegal, and can’t find any patents held by Reddit.
No need for a front end, he’s got the app, that’s the whole point
I don't remember the specific case at the moment, but a few years back I think Oracle was suing Google (or some mix of big companies) about Google replicating the Java api but with a complete from-scratch backend reimplementation. Google wasn't using private Oracle source code, just building a replacement that used the publicly published api. Google won the case, and it I remember right that established public api's as non copyright or something. Again, not a lawyer and someone else probably has the details better than I do.
But reddit is so much more than an API… and I can’t imagine anyone wants to deal with the user-generated-content hell of actually hosting that kind of platform.
Google could afford it. They're still in sore need of a good social network.