Re: Why use an unsuitable tool in the first place?
Did I make even the slightest hint that the work should be submitted full of errors?
1. The tool I suggested (focuswriter) has a spelling dictionary and checks on the fly or at the end.
2. Word is not better (or worse) in this regard.
The software you use is not an excuse for errors. However, let me point out that it used to be common to submit written works as typescript (or manuscript) and the writers did not have the luxury of spellcheckers or even error correction. And the quality of manuscripts and typescripts was vastly superior to some examples of today's works where the writer did not even bother to run a spellchecker on his or her text once.
However, it's Alastair Reynolds we're talking about. So your comment that the publisher would give excuses not to use your work is absurd. Mr. Reynolds has been published extensively and his publisher is definitely not going to give excuses not to use his work since it's basically printing money. Well, okay, I presume if he submitted utter rubbish, the publisher would firmly say 'no,' but otherwise, you're very unreasonable.
Your post reveals that you may have been rejected by some publishers. However, I would offer an alternative explanation. Whatever tools you use (or don't), they're not the reason you were rejected. And they were right -- they want "stuff" that's readable. Yours is not. It displays as three lines on my screen and I can say with all certainty that if I were to read through three thousand lines of such dubious quality, my eyes would bleed out of my eyesockets.