In order to create these elaborate toys in the first place, they need to be designed and worked out first. Hasbro and Takara Tomy have engineers in both America and Japan, and different engineers work on different projects. For example, if you asked two different people to bake a cake with only a photo reference, you’ll get different results. For many years, fans had no clue how the toys were developed, until recently, when some of Hasbro’s engineers and designers decided to be active online, allowing folks to ask questions whenever they could.
For a Transformer toy to be produced, a character needs to be popular enough (Most of the time). For example, there will always be multiple different Optimus Prime toys available on store shelves, due to the character’s popularity. Other popular characters such as Megatron follow the same rule. Basically, the popular characters consistently get new toys, but some of the obscure will often be put to the sidelines.
Rotten Tomataoes Page about Transformers One