On Hive and Steem it is a usual practice of writing big post and over a period of time many lose interest on that part. If they would start earning rewards on shorter contents and just images then we can see more traffic here also.
The truisms in your words are too evident to be ignored. I entirely agree with you that users should be allowed to post shorter contents and even original memes. As you say, it will drive traffic upwards and make many users stay. Cheers!