You’re aboit the only person that says that. I’m not saying accelerate at the pace of molasses in January. Rabbit starts as you describe are proven to be worse for gas mileage. Your MOG suffers most at street driving which is where slow smooth acceleration is how you get better mpg.
You’re not locking the tc on streets anyway as you’re not going fast enough at a steady enough speed for long wnoigh time to benefit from the tc lock up.
tc lockup is great for log steady drive at freeway speeds. Accelerating on a freeway on ramp will get you to speed faster but it’s not gonna return better mog.
I have had plenty of stock GM lockup transmissions that lock up at 20ish MPH even under moderate acceleration. My Q-Jet 700r4 as long as it had 4 in/hg or so ported vacuum on the TCC vacuum switch would lock in 2nd and so would my TBI. My 4L80E also locked in 2nd on the stock tuning.
~1/2 throttle acceleration getting the engine up near peak torque is the absolute most fuel efficient way to accelerate. I have tested it in everything I have owned, from a carbureted SBC to a 320 hp Nissan V6. Slow acceleration has not once saved me any fuel and in fact eats more fuel more times than not.
My city driving can be several miles at a time at 35-45 mph and there definitely is enough steady cruising to benifit from TCC lockup.