In 1910 the Model T had already been in production for 2 years. Remember that the Model T was designed to be cheap, so that every American could afford one.

If anything, this is more like buying a horse (not building a barn) in the "Horseless Carriage" era of the late 1800s. It was an era when cars basically looked like horse-drawn carriages but without the horses. Everything was custom-manufactured, and it was expensive. You could maybe see that these "horseless carriages" were the future, but they were still pretty impractical for the present. The world still had infrastructure only for horses, and not horseless carriages.

And yeah, if you were rich enough you might want to do your part to get rid of the major pollution problem of the day -- streets absolutely filled with horse shit. But, that didn't mean it was necessarily a practical idea to be one of the first to jump on the bandwagon.