Response to 1st post
Arguments was are well thought and grounded especially with the citations that reinforce your statements. I agree with you that Amazon started as with long-term plans, but it is now reaping significantly with short run plans. Your point on how it achieves economies of scale is well elaborated through the use of Prime service. You could have made a better post by explaining how it employs fixed inputs in the long run and variable inputs in the short term to improve its performance. Important variable inputs include labor whereby Amazon employs most its staff on a temporary basis depending on market demand. With labor, then you could have talked how it leads to diminishing rates of return and increased marginal costs.
Response to 2nd post
I agree that based on the first few years after inception, Amazon did not perform due to its long-run planning. However, I feel that most of your facts do not have valid and coherent explanations. Your post could be better if you explained a little more how improved production and service delivery has enabled the company to achieve economies of scale. Then again, I differ with your thoughts that marginal costs are associated with long run plans. I believe that Amazon has used labor as the most important variable input to avoid diminishing rates of returns from its employees, hence reduced marginal costs.
Response to 3rd post
It is true that you are a perfect example of a variable input while working temporarily with Amazon. I like how you have explained how variable inputs affect demand in the short run by using yourself as an example of a variable input. I concur with you on the fixed inputs such as vast warehouses and variable inputs such as labor on how they are bound to enhance the prosperity of Amazon. However, I feel that you should have discussed the long run nature of Amazon’s business after inception and how it realized losses in the first year of commencement of operations. Withal, your post was interesting especially with the right facts about variable inputs at Amazon.