About 10 yrs ago, when bike stuff was noticeably cheaper I figured it cost between $0.05 and 0.10/ mile to ride a bike. Intangibles being tires ridden to bald spots with carcass showing versus tire failure by large hole in sidewall from rock, tube valve failure versus tossing after 6th-8th hole patched using bulk patches. This did not include depreciation which would be ~35-50% of bike new cost
over the first 2-3 yrs. With the popularity of disk brakes that adds another $0.01 per mile cost for pads which don't seem to last as long as rim pads, but OTOH the rims last longer without rim braking
wearing out the braking surface. Tires are a big part of this, and if you insist on $45-70/tire, you are at $0.01-0.025/mile for tires alone.