MidJourney is already good enough creating illustrations for articles, book covers, etc. Not something that The New Yorker will be interested in, but better than anything you can buy for a couple of dollars or small monthly subscription.
Stock photo sites and Google Images and basic graphic filters did that a long time ago. Sure, DALL-E has certain creative possibilities that those don't, and the niches like satirical memes or "first pass" concepts in agency brainstorming meetings where it could be absolutely revolutionary tend to not be deliverables the creators get paid for. The publications giving illustrators a reliable income are usually after their consistent style, fantasy world coherence or novel ideas which isn't exactly where DALL-E shines.
There will come a point, much sooner than later, where the value in typing prompts into an AI is going to only be worth minimum wage.
The initial impressions are that production ready designs will require an artists touch. But this discussion was in the context of AA-Games and up. For indie and small games fully AI produced art may be fine.