Today there are a lot of mitigations where the steps of the paper don’t work anymore,

Yeah, that's fair to note. For a number of environments today, the base address of the stack is randomized, which is aimed at making it hard to push a static offset and exploit buffer overflows targeting the stack:

https://en.wikipedia.org/wiki/Address_space_layout_randomization

https://en.wikipedia.org/wiki/Buffer_overflow_protection

Historically part of exploiting such a buffer overflow might include the malicious code to be invoked, as a way to get it into memory, and the introduction of the NX bit to x86 permitted OSes to mark regions of memory to the CPU's MMU as only being able to contain data, not executable code. This meant that it became significantly harder to have a buffer overflow that both seized control of the instruction pointer and contained hostile code.