The area this article is talking about was oak savannah:
Within these oak savannas, which were interlaced with prairies, tree crowns covered between 10 percent and 30 percent of the ground. They were essentially a transition between the tight deciduous forests of the East and the fully open grasslands further west.
Modern bikes being less maintainable is largely on the extreme low-end like Walmart bikes, or extreme high end carbon-fiber nonsense designed for rich weekend warriors.
Best if you find a shop that deals in second-hand bikes and get a cheap one. A bike that has been maintained by such a shop is likely to continue being maintainable. Plus you may not know what kind of bike you like til you ride it for a while so don’t spend too much for your first one.