How many times have we heard that?
Tank versus anti-tank, measure versus counter-measure versus counter-counter-measure; sometimes the tank is up, sometimes not, but we have been hearing this since the Germans invented a 13mm Mauser elephant gun as the first anti-tank weapon.
How would you have taken Baghdad without heavy armor?
If indeed heavy armor is of no use, why do the Israelis keep any tanks?
It is the difference between breaking the speed of sound and breaking the speed of light. One is an engineering barrier, the other is a fundamental physical limit; savvy people know the difference. The physical limits of armor have been known for a long time, but designing a weapon that actually breaches these limits is not trivial.
There now exists anti-armor systems for which the only defense (barring exotic sci-fi tech), requires breaking a fundamental limit of molecular materials. Until now, they were only engineering limits, but the US has been trying to design anti-armor systems that functioned past the ability of physical armor to dissipate them for some time. Some of the currently deployed systems are very powerful, but we know that it is physically possible to design a system that will defeat them. It was a great coup for the anti-armor design teams to devise weapons that operated at parameters beyond the limits of physical materials to defeat them. We will be deploying unstoppable anti-armor systems over the next couple years. The rest of the world will follow in a decade or two.
Arms designers have always known this was possible, but it took many years (and US military design teams) to design real weapons with these capabilities that were capable of operating at these extreme parameters.