I have tried making this point before and am surprised you still hear the every day argument. Every play is primarily batter vs. pitcher. So a starting pitcher that pitches 7 innings is in on 39% of the plays (7 / 18), versus the hitter at 5.5% of the plays (1 / 18)
Sometimes I'd really like to sticky quotes like this. Starting pitching is the most important position on the field, and in my opinion it isn't close. I'm not saying draft a pitcher if someone like Jackson is the best available at 5, but this once every 5 games thing should not be the reason to not draft or pay money for good pitching.
I'd note that the starting pitcher that goes 7 innings will also see a very similar amount plate appearances as a hitter over 5 days... and that pitcher has far more control over the outcome than than the hitter.