Simply not true. The Russian model, as an example, T90 is a very survivable tank and utilizes 3 layers of armor, yet is barely more then 1/2 the weight of Western tanks. The West has gone with the same falacy of Hitler, bigger is better. The Kind Tiger was 70 tons but was a crap machine fit only for light mobile defense work. The Panther was much lighter and a lot better.
The race between offense and defense is nothing new and has been going on since warfare started.
You also ignore the advance of technology. New stronger and lighter polimers are constantly being developed, along with new and improved power packs/plants that make the weapon system more maneuverable. The main survivability feature of a tank is not armor, for that you build forts or assault guns...it is maneuverability, the ability to out maneuver your enemy, beat him to the objective, hit him from the flanks before he has time to prepare, in other words...run the bastard over.
By the way, the T90 has very effective anti missile defenses that the US/Western modils don't even come close to. Or in most cases even have anything in development that's equivalent...and this is already long time in production.
The T-90 is "very survivable." That's a sentence just BEGGING for some Clintonian parsing...what does it MEAN, exactly?
The "top attack" issue isn't going to go away anytime soon, because main gun rounds are going to be using it. That means a LOT of armor on the roof, and that stuff gets HEAVY.
If an MBT was about to run over me, I might panic as well - but I don't plan on fighting tanks with my fists. In my screen, a MBT is just another space invader to be zapped. MBT's may not have outlived their usefulness but they won't be useful much longer. I also note that you can't really use a "tank formation" in urban areas or over mountainous terrain (as we have all seen in the Balkans).
You also ignore the advance of technology.
BWHAHAHAHA! Some current production antitank weapons have over-the-horizon range, video guidance, and cost under 20K. How far can your tank shoot? How much does your ammo cost? Can you shoot around mountains like we can? Newer precision guided weapons are fire-and-forget/autonomous designs that can hunt down tanks all by themselves. And they get cheaper all the time...