Almost everyone makes grammatical mistakes, typos, and other logical errors when writing. I've been in the publishing business for over 20 years now and I've only met two people who don't make errors -- and the editor of this blog is one of them!
Historically, a book or magazine article went through numerous edits. That's happening less now, in most publishing mediums. It use to take a long time to work a book through the publishing process. If a book was rushed, others were dropped temporarily. Now, everything is rushed and consequently, the content receives fewer edits and fewer editors view it (not redundant, they're not the same thing). This change is even more pronounced in the electronic format. What use to receive several edit passes, might receive one or two before it's online!
Author(s) and editors aren't any less intelligent than their predecessors. We're just responding to audience demand -- in an effort to remain competitive, we have to supply it... albeit sometimes with an error or two.
I think some people have little emotional attachment to the change (that would be me). If I let it bother me, I'd go nuts! Besides, we are an innovative species -- this "problem" will eventually create a solution.
I use spell check and am thankful for it daily.