RAM is not in the same league as Ford and GM economically. Ford is the fourth largest automaker worldwide and has very deep pockets. GM is next at number 5. Stellantis is distant 9, but that also includes all their many other auto divisions, not just RAM. I'm amazed RAM, with its much more limited budget, competes as well with Ford and GM as they do.
They can probably only economically offer one V8 option for the 1500 (special edition TRX excluded). Given the choices, the 5.7 makes sense. It's a good compromise of power, torque, and efficiency and it doesn't interfere with the 2500 sales. It would be great if they also offered the SRT or the 2500's 6.4, but that's not going to happen. I don't think they could justify it and they would probably lose money doing it. Besides, the marketing team figures that if someone really wants more towing capability, they'll just choose the 2500. They simply can't practically give you all the engine options that Ford or GM can. Look at Ford, their F150 option list is insane.
You can question RAM's marketing strategy, but for a relatively small truck division with limited resources, they're doing incredibly well against the big boys who have far more money to throw around.
Car and Driver rates the 2022 RAM 1500 the best full-sized pickup. I can't imagine how much that ****** off Ford and GM with all the massive $$$$ they've invested, while RAM bests them on a much more limited budget.