Bread gets moldy for the simple reason that molds produce millions of spores. Those spores are so very tiny that they float everywhere in the air. To see any of these images full size, just click on them. Please note that the scale markings are twice what they should be. It is 12 mm in diameter, and show the extremely low magnification that SEMs are capable of, still with good resolution and very great depth of field.
Bread mold is really one of the simplest forms of fungus.
It starts growth from a spore, which grows into a mass of filaments called mycelia. What you see is not really a spore, but a capsule holding the spore. When the spores are mature, the capsules break open at the top, as shown above. The very highly magnified image on the right shows that the knobs on the spore capsule were not really randomly arranged, but were strings of beads. It answers the question of what is a successful organism.