Active defence has limits, sure. There's a long dance between attack and defence.

My point was that the tank isn't doomed there - if vulnerability to anti-tank missiles was the only issue, armies would research and deploy active defences everywhere and the tank would be important as it was.

I think the problems are elsewhere. When infantryman can deploy offensive power outranging the canon, one needs to ask why have the tank when the infantryman requires so much less logistics. If say, the tanks could use a heavy mobile laser, than the equation would be different.