This. I'm not the type of member to care if you take my advice or not tbh. I'm just offering it. I personally keep crickets, dubia roaches, superworms, Hissing roaches. I feed them all a variety of veggies and or bug burger in a dry form. I do use cricket crack as well. All the stuff you feed your bugs, equals healthier chameleons.
I worked in the pet industry. Convenience is a huge thing to pet stores. Mealworms are easy to keep, cheap to buy in bulk, and no pet store plans on keeping an animal long term, so their immediate nutritional needs are not a concern to them.
Concerning Vets, I've had 'vets" give me some of the worst info ever in this hobby. I once had a tree boa with a mild mouth infection. I knew what I needed when I went in and explained it all to the vet. The moron then told me the temps to keep the animal at and a few other things. I then pulled up the correct temps on my phone for emphasis as I told him I've been keeping reptiles for 40 years, a hell of a lot longer than the years he had been a vet. A good reptile vet is worth their weight in gold to you and your hobby. Avoid the others.
Mealworms suck as a staple diet. But what do I know?