I guess this line of discourse begs the question I was contemplating before I bought the bike in the first place. I surveyed the facilities as work and at home and made the estimate that if I locked it if outside overnight, it would last about 5 years, while I'd make it about 10 years if locked inside. I considered the life of the bicycle over when it was cheaper to replace then to repair.
As far as the initial cost, in my opinion it was necessary to have the bike in my possession before starting the calculation, therefore I front loaded the costs of bike and equipment (minus the helmet and clothing I already had). That way, a bicyclist would see the true cost of bicycle ownership and how long it would take to hit the magic cross-over point where every mi after a certain distance was "free."
For more that will be roughly 125 round-trip commutes or around 9 or 10 months of commuting.
If we're assessing the ability of a bike to be used as replacement for a car/bus, this seemed like a more accurte predictor of true costs, as most don't by bikes with a payment system.