this seems doubtful to me. Reddit has tons of legendary threads, AMAs and is its own library of content at this point, similar to YouTube. Sure the tech could be replicated but the value is all in the content it generated.
Of course, then people might start looking at the fact that they are giving away valuable property to Reddit in return for access to a simple forum site...
Most users aren't going to do this. Really, the reddit folks should just go all-in on tailoring their official apps towards the most casual, highly "engaged" content consumers, and target most of their monetization towards that kind of user. As a bonus, make it trivially easy to post casual content directly from the app. Who cares about "objectionable" content when they'll have so many cat pictures and cute/funny memes to run their ads next to.
Not only that, but if Reddit were to strongly disallow any or all of the above we have seen how EASY it is to simply clone the tech and re-host. There have been stories about certain communities being exiled from Reddit only to spring up just as quickly elsewhere with more or less the same exact user experience...