Editing Tank (section)

===Speed===

Like what we've described above: it wasn't that hard to stop a tank with the proper armaments (or at least avoid it once spotted) and once your opponent has the guns to stop it, your hulking behemoth will slowly turn into a liability soon enough. (And even if they didn't have the guns; that makes your tank too-slow of a threat, which begs the question as to why you have it there in the first place). 

Tanks were also pretty vulnerable on their own, requiring infantry support to deal with targets at close range (the co-axial gun only had limited elevation and was slow to aim as the entire turret had to face the target, and the pintle-mounted gun was limited to the line of sight of the gunner) as a nutter with a powerful-enough explosive could easily run/sneak to an unsupported tank and blow it to smithereens, or disable it (which pretty much meant the tank is still toast). 

Nazi Germany got around this problem by using mechanized infantry (troops transported in vehicles) to support their armored forces, so everyone picked up on that and started making tanks fast enough to keep up with infantry transports to create a combined-arms assault, allowing tanks to deal with hard targets while infantry dealt with other targets that were too small for the tanks to take care of.

So, people started distancing themselves from heavyweight tanks, and started using lighter, but more faster tanks in modern combat (plus advances in modern technology made it that even a medium tank could still be as survivable and powerful as a true heavy, while still retaining maneuvrability).