It is not a difficult thing to see evergreen contents on steeemit. Developers just need to make a tool which may filter the quality contents and after verifying by the community that content may be included in the hall of fame tab on steemit or a new app may be launched in which only quality content can be shown.
There are many criteria to select these kind of contents. One is the number of votes received by the post, but it can be manipulated. So, the best thing would be to manually select some quality content by the @curie, @adsactly etc and opinion of the steemit users may be sought on the quality of the contents. User can rank the content according to their choices. Accounts of bots and automatic voters should be excluded in this process. Also the post should not receive any reward for being selected as hall of fame post.
Only vote of users with certain reputation for e.g. more than 50 should be considered. Automatic voting should not be allowed.
There is another way to find out the quality content. Users should be allowed to select and submit the posts of other users. The top selectors can be rewarded to find quality contents. This would really be great!