JohnFrum is discussing:

The problem the tank has is it doesn't have to useless to be obsolete. It just has to be a little too expensive, a little too vulnerable. IMO the MTB has reached that point in most armies. A tank can't get much larger or heaver or it wouldn't fit on roads and can't cross bridges. So MBT armor is unlikely to improve much. It's certainly not going to improve enough to defeat shoulder fired anti-tank missiles. Nor are countermeasures likely to save it cuz MBTs cost million and NLAWS cost thousands. So if even if some new countermeasures can stop1 NLAW it probably can't 2 or 3 NLAWS. Meaning the best counter to a MBT going forward is an anti-tank missile.

If we're now in a world where the MBT's #1 threat is infantry and it's #1 protection is infantry then Why does it have that big gun and thick armor? The armor doesn't protect it, the gun is overkill for shooting at infantry. What realistically can a MTB do that a much cheaper lighter, more agile APC armed with anti-tank missiles and an automatic 30 mm cannon can't do?

IDK if the MBT is completely obsolete in all armies everywhere yet, but it's getting there. The US army can probably still afford to field MBTs even if they aren't as useful as they once were, but most military would, be much better served to ditch the MBT and invest in shoulder fired anti-tank missiles instead.