[Mobhack]

Early MBT
(prior to proliferation of ATGM)
- as WW2, but with more infantry mobility due to the prevalence of APCs post war.
RCL on Jeeps and infantry-AT weapons that can reach out and touch MBT make closing with infantry a bit more problematical than later WW2 (panzerfaust problem but with more range)


Middle MBT period:
(With effective ATGM, and no technical means for tanks to counter them. Effective HEAT main ammo is widely available in tank and even little scout car guns)
Tank is not obsolete but they cannot do the WW2/early MBT period thing of sitting on a hill and dominating the battle if protection is sufficient, as a little missile team can plink them or perhaps even a Saladin or AML-90 can.
You need to use arty/smoke/night and manoeuvre warfare to deal with ATGM.

Late MBT period
MBT composite armour packages and reactive armour etc deal well with HEAT. So light AFV cannon back to low risk, and conventional missiles (not top attack) to irritants. MBT is now back to "top dog", but is expensive and losing one is painful.


WW2
If you invest in heavy armour, then that is usually a safe bet. Your tanks can generally manoeuvre in the open in front of an enemy, unless they have a massive over-match in ATG to your armour (88s on Sherman etc).
Infantry generally not a major threat to armour until panzerfausts and PIATs arrive, and these are not able to reach out and touch you beyond a few hexes.

WW2 has massive technical changes in a few years as technology advances.

MBT technology does advance, but not in the one war time frame so much - it is by decades. So upgrading less necessary as new models and tech don't arrive every 6 months or so. (if there had been a world war of 5 or so years duration then that would have likely occurred as in WW1 and 2)