Re: few days?
It's an interesting point of semantics, the hardware available in 1979 has been used to create the next generation of hardware, and then the next generation of hardware and then...
Ultimately they used a better algorithm than straightforward brute-forcing, which was to build better technology first and apply that.
There's a real lesson though, don't judge the expected lifetime of your security measures against today's hardware. If in 1979 Ken Thompson had relied on his password being secure past 2019 based on what brute-forcing with then-available technology could do he would now be out of luck.