Imagine a Tamiya 1/35th model, scaled up to 1/16th in every respect. It would make even a Heng Long look high-tech. At a large scale, articulated, functioning suspension, individual track links, along with a higher level of detail are all to be expected. Instead of being molded in or completely omitted, they have to be molded separately. You go from less than a hundred parts to over a thousand. Then if its meant to be RC, it would have to be built to actually take some abuse. There are large scale tanks that were designed as static but converted to RC that suffered durability issues from plastics not being resilient enough and flexy construction resulting in cracks.

Its not just about scaling it up, there's a lot more in it once you take a closer look.