Normbear, it is true that one doesn't need to use quantum physics to deal with the question of the missing apartment (unless one likes doing massive amounts of calculations with infinitesimal numbers) when assuming determinism will almost certainly give the same answer. Engineers (and statisticians) make assumptions like these all the time - when convenient - in order to get the job done.
However, assumption is not proof (not even when it leads to the correct answer) - it is a logical flaw known as "begging the question" (a form of circular argument).
If the universe originated as a teensy-weensy singularity then quantum physics rather than determinism is almost certainly the way to go.
There is a point at which quantum uncertainty settles into macro level determinism. If I come home and find that my apartment building is no longer there, I can be fairly sure that its relocation is the result of the deterministic laws of physics rather than quantum effects. The predictability of our human level world relies on determinism.
We can't precisely measure both the position and momentum of a particle (because the measuring instrument interferes with the particle) so we use quantum theory (essentially a branch of statistics) to analyze the whole possible range of behaviors that may result from an observation.
In other words, even if we "knew" the exact state of the universe at any one time, there would be a number of paths that the universe could follow from that time onwards.
This analysis doesn't even deal with the question of whether life is simply the sum of the components of the universe or whether it is something else altogether.
Since we don't actually know, Dilbert may ASSUME that the universe is deterministic - ie: he is entitled to his beliefs.
Success or failure can only be determined from a limited, short-term point of view. Everything was "meant to be"--that is, grew out of preceding !$%*!$%*!$%*!$%*! you take Science as a reliable way of solving problems. The humor, for me, is that Dilbert responded to a small-minded question with a big-minded answer.