That correlation, when controlled for other factors, is weak though.
But you could make the argument that it's easier to turn a TV off when a game is boring where as most people won't leave the ball park because it's "just" a 2-1 pitcher duel. In fact, the Red Sox saw significant increases in attendance on games that Pedro Martinez started. This suggests teams are more inclined to watch games started by better pitchers. Ask yourself, would you rather watch Kershaw vs Felix where scoring is very likely to be low scoring or games started by worse pitchers where scoring will be higher?
Again your narrative makes sense but there just isn't any evidence that it's actually true.
High profile pitchers can bring in the crowds. Dontrelle Willis for the Marlins for example several years ago. However on average I do believe high scoring games bring in the crowds. My 'evidence' may not be true. But attendance did spike when homeruns were flying out of the park and has decreased when pitching has become dominant. If the sport is as popular as ever you would think more people would show up to games.