I do slightly disagree, the main problem with mechanical fans is the gap between the shroud and blade needs to be large (as the engine moves around a lot) which kills efficiency. An electric fan “seals” really well meaning it makes use of its power draw much more efficiently.
And as above, the mechanical fan is based on engine rpm, not on heat load. So if you do start to overheat and drop to idle, your airflow drops a lot. Likewise if you turn your engine off that stops airflow entirely. Additionally an electric thermofan can be set to higher rpm when you switch the aircon on, whereas a mechanical fan doesn’t really help if engine temps are under control.
So again it’s one of those things where if done properly, an electric fan can be really good. However it requires a lot of cost and effort... too many people have tried the cheap/easy path then been disappointed by the results.
I agree wholeheartedly on the efficiency, but I don't think it can be so much more efficient that an electric could ever dream of matching a mechanical fan. The electric ring-style fans are typically 50% efficient in optimal conditions, so poor shrouding losses for the mechanical would have to put it at maybe 3% efficient to be beaten. I feel like there is no way it is that bad even with a 1" gap all the way around, not with the sheer volume of air I can feel blowing out even at idle.
ShieldSquare Captcha - https://iopscience.iop.org/article/10.1088/1757-899X/52/4/042008/pdf - these guys got another 5% out of a typical ring style fan by addition of an anti-recirculation ring.
Your second point raises driving style and people doing it wrong. When things get hot, you need to drop gears and rev the heck out of it, not "give it a break". Not exactly intuitive I guess. At high RPM, you have more than enough cooling airflow for continuous full throttle usage in hot weather, far hotter than Toyota's 104F/40C maximum, even with little to no ram air affect. Of course, that's hard to do when crawling around through difficult obstacles, so that's a plus to the electric fan.
Overall I like the idea of the electric fan because more horsepower (duh), better fuel economy, and realistically you don't need that much cooling unless you're working it hard when it's really hot out. That said, to get something that would compete with the mechanical fan for really hot weather in SoCal desert mountains would be expensive I think. What would make me most comfortable for the occasional extreme environment use is dual front high mounted electric fans with a shroud (yeah I know, a front shroud reduces ram air for freeway use, but with dual fans you've still got most of it uncovered and the covered part is behind the bumper anyways), while the engine would get a flex fan mounted to something like an AC compressor clutch so it could completely disengage. Then you get the best of both worlds.
IIRC from the wit's end turbo thread dyno results, stock only gets 130-140hp at the wheels, so that 5hp at 3500rpm to 9hp at 4500rpm is definitely enough to be felt (about 3-7%). But you'd probably get just as much gain by going from 15w-40 to 5w-30 oil, (that's not something I'd risk, I like my rod bearings how they are).
I don't think you'd be able to feel a gain at normal cruising RPMs though, it was down to 4hp at 3k rpm and it just keeps going down from there.
Edit: Or alternatively, if I put on a cooling fan like that video and it handled a towing a 5000lb trailer up the grades (creating a situation for full throttle without a lot of vehicle speed) on a 110F day in desert valley I would be totally comfortable from that point on. I haven't had an opportunity to test it out like that, but the stock system should handle that no problem if you let it sit at 3.5-4k rpm the whole time.
