The fact is that anything that increases the amount of you or the rate of you over time over the bare minimum needed for survival is an increased cancer risk... there are other causes like exposure to radiation that actually damage cells and so on as well.
Ultimately the question isn't if there's a link to cancer, it's how much something is increasing your risk of cancer relative to the alternatives. I suspect artificial sweeteners are in general for most less risk than consuming vast amounts of sugar, gaining lots of weight, becoming inactive, and increasing their cancer risk that way but who knows. Obviously if you ommit everything but consume the bare minimum sugar you need for survival you'll have a lower risk... good luck with that in modern society and diets
Your point is only valid if it actually lowers sugar and other carbs intake. Which isn't the case for most people.
Next to that. With diet drinks people drink more since they feel like they can get a way with, some do with sugar variants as well, but seems like more people binge drink diet versions which could lead to higher exposure relatively.
The has been processing sugar for millennia, these chemicals are pretty new.
More people need to stop consuming garbage that wouldn't have been considered food 250+ years ago.