Many automatics these days are manual transmissions with a computer controlling the clutch. They have nothing in common with the slushboxes of old, the oil is just for lubrication.
ZF 8HP is still a traditional torque converter transmission. Most high performance or high torque applications use that design. Dual clutch automatics or automated manuals can't take it.
Citation needed. By truck if you mean commercial truck (lorry, artic, etc.) then no, Allison still makes hydraulic automatics which are very common in vocational work the world over.
Even slushboxes tend to aggressively lock up the torque converter. It's usually only in a "fluid dynamics" mode for brief moments. (Except maybe on a gentle hill start)
It's worth mentioning hard acceleration causes a torque multiplication to occur in torque converters vs a slow acceleration does not (check me on that). Once locked up, multiplication no longer occurs. Thank you hot rod magazines of the 90's.
I mean, certainly the VAG group likes to use their dual clutch automatics, but "true" torque converters are still very common. ZF makes them for like a million different cars, and AISIN makes them for the Volvo and Geely group.