Very true. For a few years I was the Facilities Manager for an R&D lab. Many PHD chemists and engineers. Some with multiple PHDs. Most couldn't write a coherent email to save their life. Us mere mortals joked that the ones that wore slip on shoes did so because they couldn't tie a knot.I was an editor for a publisher of microbiology journals. You'd be surprised how many Ph.D.s aren't great spellers.
U.S. ones, anyway. Papers submitted from Europe and Asia often had impeccable spelling.
As the cover letter accompanying one resubmitted paper said, "The English has been corrected by our Swedish author."