Largely true, though exaggerated.
New dishwasher main wash and final rinse temps are too low. Most people run the Normal cycle and largely scrape and rinses dishes to the point that the sensor machines won’t run a more aggressive cycle. As others have said, no more chlorine bleach in detergent, as well as phosphates certainly aren’t helping the situation. While enzymes and activated sodium percarbonate help, they aren’t as strong as the products they replaced. The new machines also use less water per fill which means more concentrated pathogen count per unit of water used. So, yes the ad is correct, but I don’t feel that it is as big of an issue as they are portraying. I have come across machines that have been absolutely caked with junk, but no complaints of illness from what I recall. In fact, our house was previously owned by a family practice MD, and she left the dishwasher and refrigerator quite dirty. Didn’t seem to be an issue for her.