I've been aware of or part of the maintenance performed on several cars from the late 60's to present. My father owned a service station since the 1940's and my uncle owned another. I can only speak of the cars I am certain of such as my father's, brothers my children's and close friends, but this is serval cars for over 50 years totaling about 2 million miles. I do not know of anyone using a cleaner on any kind of regular basis. Sometimes when some problem existed that could not be easily fixed, some "wonder fix" in a can might have been thrown into a tank but only as a last resort and that never worked.I've seen issues, even on my own engine. It will run like **** and idle like **** and be low on power if I go a long time without cleaning it. Also have a coworker with an Audi that had problems with hard starting/stalling that was completely solved by an intake valve cleaning I personally did myself.
Fuel injectors need extra care to keep them clean and running right, I got lazy with the techron once and it threw a lean under higher load code at me.
I don't want to put words in your mouth but is sounds like you are using fuel additives on a regular basis [ perhaps every 1,000 miles]. And that if you don't use these products your car runs poorly. I suggest you change where you buy your fuel. No modern automobile required extra additives if quality fuel is used.