I actually change my mind, if anything I think 4chan might become worse - assuming no changes in terms of moderation. The bad-faith, ragebait, trollposting people obviously dont wanna wait multiple hours to get one reply. People that make good posts and actually want to discuss things are much more likely to and are thus, according to me, more likely to stay (or at least mainly post) on altchans with less activity
It might actually only get worse due to the ratio of shit posts to good posts increasing