Why isn't the woom GO available in sizes 5 and 6?

Since older children have different requirements for a bike than children of kindergarten and preschool age, we have made a clearer distinction between the sizes when developing our woom ORIGINAL models: 

• The woom GO is available in sizes 1 to 4 and, thanks to its beginner-friendly geometry and features, is the perfect balance bike or bicycle for learning to ride easily, safely and with lots of fun. 
• The woom EXPLORE is available in sizes 4 to 6 and was specifically developed for the needs and wishes of older children in terms of both features and appearance. 
• Also NEW: Size 4 (20 inches) is now available in two versions – as the woom EXPLORE 4 with Vario stem and disc brakes and as the woom GO 4 with BMX handlebars and rim brakes.