How would I trust the programers who implement automatic memory management that they are not going to make any mistake?
It's much better to push logic from being manually re-written over and over by tens of thousands of different programmers, to being built into a language/tool/library by a team of a few hundred experts and then robustly tested.
Nope, doesn't work. Then you have to trust that the programmer who wrote the assembler didn't make any mistakes. Real programmers program in octal.
This is true, but the actual solution is safer assembly. ARM is heading in this direction with PAC/BTI/CHERI. Intel, being Intel, tried adding some and it was so broken they removed it again.
It could go much further.