Racing divers would shift exactly like automatic because they need to tease the best possible acceleration out of a given engine configuration.
Day to day driving is wildly different from that, there are only very few situations where people come anywhere close to the maximum acceleration their car would offer. With manual transmission, you can attain submaximal acceleration by flooring the throttle in a low gear. This is much more fuel efficient than getting the same amount of acceleration with a throttled engine at higher rpm. Automatic transmissions make that more difficult or even impossible (depending on implementation).
Worst case: people are unhappy with the acceleration they can get at low rev, because the transmission only allows low rev at throttled state and they don't consider it socially acceptable to rev up. The engine would be capable of much more torque at the desired rpm, if only the throttle could be opened without the transmission shifting for higher rpm. Next time they will get a bigger engine that will be throttled even more. ICE inefficiency rises with high rpm and closed throttle (opening the throttle raises power output more than consumption). Ideal ICE efficiency is when the gear is selected so that torque at open throttle matches the power demand. Manual can come much closer to that than automatic. (Unfortunately, many people don't know that and drive manuals like automatic, e.g. never at really low rpm, never at really open throttle, because they think that opening the throttle would be wasteful)
I'm not going to say "you're wrong" but I think there are plenty of situations where you know or can anticipate what gear you need to tackle a certain scenario, where an auto simply can't know.
For example, a set of 90 degree bends with (very) short straights between them (this is a real scenario where I live and why I've thought about this at length already). In a manual, you might ride the entire set of bends out in a low gear so you get both the most acceleration between bends and not have any gear changes mid-bend so you're ready to accelerate out quickly. An automatic, on the other hand, would be inclined to change up gear between bends and then have to change back down again once you want to accelerate out as it wouldn't really know what was going on.
My car's transmission has a wide variety of options, including a "race" mode, and I usually drive manual instead, because the semi-automatic options seem to be terrible at anticipating anything and coaxing them through throttle alone is an art beyond me.
> I'm not going to say "you're wrong" but I think there are plenty of situations where you know or can anticipate what gear you need to tackle a certain scenario, where an auto simply can't know.
I know what you mean, the similarity between an automatic and a race driver was only meant to be about the specific context of fuel efficiency, not about shaving of a few more second from your lap times. But in the end, both of those wildly different optimization goals can benefit from a driver's superior ability to anticipate future power demand. And both goals create comparable challenges in "coaxing them through throttle alone", which describes my frustration with automatics pretty well. In day to day driving, people seem to want a certain amount of acceleration at non-aggressive rpm, and automatics that make it hard or even impossible to tap the full low-rev torque of a given engine make people buy bigger engines than they would need if the transmission would better support their use case.
Give me an automatic that allows me to apply unrestricted (by backshifting) torque at any rpm and I would look at it much more favorable.
Day to day driving is wildly different from that, there are only very few situations where people come anywhere close to the maximum acceleration their car would offer. With manual transmission, you can attain submaximal acceleration by flooring the throttle in a low gear. This is much more fuel efficient than getting the same amount of acceleration with a throttled engine at higher rpm. Automatic transmissions make that more difficult or even impossible (depending on implementation).
Worst case: people are unhappy with the acceleration they can get at low rev, because the transmission only allows low rev at throttled state and they don't consider it socially acceptable to rev up. The engine would be capable of much more torque at the desired rpm, if only the throttle could be opened without the transmission shifting for higher rpm. Next time they will get a bigger engine that will be throttled even more. ICE inefficiency rises with high rpm and closed throttle (opening the throttle raises power output more than consumption). Ideal ICE efficiency is when the gear is selected so that torque at open throttle matches the power demand. Manual can come much closer to that than automatic. (Unfortunately, many people don't know that and drive manuals like automatic, e.g. never at really low rpm, never at really open throttle, because they think that opening the throttle would be wasteful)