Yes, but you are ignoring the time factor. Assume I'm going to die of natural causes in 60 years. If it takes a minute to guess a 6 digit number, that is real

Yes, but you are ignoring the time factor. Assume I'm going to die of natural causes in 60 years. If it takes a minute to guess a 6 digit number, that is really bad. If it takes 1000 years to guess a number that is larger by dozens of orders of magnitude, odds are pretty good I'm going to die of natural causes before the attacker guesses the right number.