The universe seems to be a single energetic conduit. Whether calling or banishing, getting help or approval from a water spirit, concentrating energy on an effect (prayer/chanting/etc.), or speaking audible words to a friend, everything is touching, so to speak, with no need for an intermediary medium. The extra ritual is, for those who can circumvent it, a sapper of inner power.
EDIT: I suppose I should clarify that by "sapper of inner power" I mean that, keeping in mind that life on this earth is a limited thing, rituals take time. In learning to make use of every moment of life, in my humble opinion, the end result of learning anything is to do away with anything superfluous.
An internal combustion engine combusts fuel and generates work, but before that work may be applied, some of the energy never makes it to the work piece. (simplified) Electricity travels through wires to spark plug-->spark and compression ignite fuel-->cylinder is compressed-->rod turns crankshaft-->crankshaft spins flywheel-->gears, rods, and pulleys are rotated-->transmission turns one shaft speed into many-->drive shaft turns gears in axle-->axle moves wheels-->wheels propel automobile. In all, only a fraction of the power generated by the combustion reaches the pavement. The rest of it is eaten each time it reaches a new system it has to power.
By the same token, a ritual mucks up the path the power takes to the results. Sometimes, this is unavoidable. The ritual also focuses intent, so maybe the wielder learns the ritual, first, and can subtract what he no longer needs as he sees fit. Religious prayer, shamanic intent, using chi, invoking psychological understandings, and modern psychic capacity--they're all the same. They have different names, and different cultures have socially agreed to see the universe and its workings differently, but they all have the same result: work done for energy applied to an intent.