Unless you're buying some really crappy cars or bikes, they generally last for several years or decades, compared to the estimated month-6 months lifespan of e-scooters. (Bird has newer scooters coming out that are supposed to last almost a year. Almost a year. For an average of 3 rides a day.)

When you're arguing that your mode of transport is green but it only lasts a few weeks with relatively sparse usage, then the manufacturing carbon footprint is absolutely relevant. When the mode of transport lasts for decades and the manufacturing footprint is spread out amongst millions of others vehicles, the manufacturing footprint isn't very relevant.