No, the film is technically correct. There can be anterograde amnesia to a lesser or greater extent. Extreme anterograde amnesia can be very debilitating. (See the anecdote farther down.)
Anterograde amnesia refers to loss of memory for events after an incident. Often such cases are examples of what are known as "pure amnesiacs." Therefore, a person can’t store new information in their long-term memory. So it is possible to forget everything between the time of the incident and the point at which some recovery starts to take place. But even after recovery begins, anterograde amnesia can continue to make it hard to form new long-term memories.
Patients with anterograde amnesia quite often show normal memory for events prior to the incident responsible for the memory deficit but have severely impaired ability to recall information about events occurring after the incident.
Whereas with retrograde amnesia there is almost always a gradual restoration of most of the lost information, with anterograde amnesia there is quite often no such recovery and patients are left with a permanent and debilitating condition.
When I was in grad school in psychology, one of the psychology professors, Joe Notterman, had been bitten by a lab monkey and contracted a strange and rare form of encephalitis. He nearly died, but his wife, a physician, tried an experimental treatment and saved his life. However, after recovering, he had anterograde amnesia. He still remembered information prior to the incident, including what he had learned and done in his field of study. But he was thereafter plagued by an inability to consolidate short-term memories into long-term memories. People had to constantly remind him of things he'd forgotten after a day or so or, occasionally, after just a few hours.
He finally recovered somewhat, but was always bothered by some lingering anterograde amnesia as long as I knew him. (I lost track of him after 1976 and discovered only recently that he died at age 90 in 2013. So I don't know if he ever recovered fully, but I hope he did.)
The difference between stupidity and genius is that genius has its limits. -- A. Einstein
Good to know.
Thanks for answering, pt100. Very informative and interesting post. And very well written!