The parents probably don't make their brats say "trick or treat" because the little shits are autistic or non-verbal or some other nonsense, or they're lazy. There are a lot of trashy parents out there too, so they probably don't bother teaching their kids how to say thank you either.
And I can't speak for anyone else, but trunk or treat is bigger in my area than traditional trick-or-treating. Because I guess the little bastards can't even be arsed to hoof it around town looking for houses with lights on now. I was a fat fuck of a child and I still hustled my ass around for two hours!
Like I didn't even see anyone out on the street after work in costume when normally I have to dodge herds of kids with their candy sacks. So there's no longer even the thrill of going to see people's cool Halloween decorations. I remember when I was a kid, this one particular house went all out and would have people hiding in piles of leaves that would jump out and grab your ankles, and someone dressed as Frankenstein's monster that would chase you out of the yard. You had to go around the entire house full of monsters and lights, and if you made it to the end of their setup, you got full-size candy bars. I bet nobody does that now because of all the little awtards who are triggered by everything.
But stuff like this isn't fun anymore because everything has to be so sanitized. No scary costumes because Junior might cry, a brat with a blue pumpkin means they're a tard and you have to accommodate their horse shit, nobody says "thank you" because you should be honored they showed up in the first place, and I'm sure some people get bitched at for not having enough gluten-free/dairy-free/allergen-free/organic/vegan treats because every brat is allergic to everything now. The adults are probably just out waiting for a nice photo opportunity of their brat in a costume for Facebook and that's it.
This is why more adults should trick or treat. They would be much more appreciative and fun. Kids and their handlers just suck all the enjoyment out of every holiday now. I never hand out candy, but if I did, I'd sooner give it to an adult who put effort into their costume and who has enough manners to say thanks for the free snacks than an ungrateful brat and their entitled parent.