Tanks were created to cope with two dominant threats: small arms and artillery shrapnel; the WW1 battlefield of machine guns and massed artillery. They've been improved to cope with some new threats since, but the number of threats are multiplying rapidly. The cost and complexity of tanks is exploding trying to deal with all of militarized model airplanes (Bayraktar et al.), guided artillery rounds (BONUS), long range armor seeking missiles (Brimstone), guided mortar rounds (XM395), intelligent anti-armor mines (PTKM-1R), man portable antitank weapons (Javelin/NLAW/Stugna-P/...), improved RPGs, etc.
In a world where there is a Stugna-P "behind every blade of grass" tanks become a liability. I think they'll be scaled back to niches; there will probably always be a need for a big chunk of metal to push through and blow holes in things. Going forward though, the German Blitzkrieg model or Russia's Horde Of Armor doctrine is dead when the combatants are not greatly asymmetric.
I think that's a slightly skewed way of looking at it. While there's some nuggets of truth there, the better way to look at a tank is that it provides highly mobile firepower, combined with enough protection to get in there and do it's job. And that job is to support the infantry by, as you stated so well, "blow holes in things" (Quickly, might add!)
But it never was meant to operate on it's own. And when it did, it was either lost in large numbers (Russian tank charges in WWII) or was in all actuality a fluke (Your Blitzkrieg example. See The Chieftan's video on the Battle of France in WWII on why this was such a reckless thing to do, followed by reading on the Battle of The Bulge on why it didn't work a second time.)
Tanks unsupported by infantry are a liability. However, infantry, unsupported by tanks, can be a liability as well when attacking an opponent who's well fortified and/or has heavy weapons. When tanks, infantry, and artillery work together (combined arms theory), then the danger posed by ATGMs and the like is greatly reduced. Armies have been reminded of this numerous times last century, and each time a renewed emphasis on combined arms fixes the balance.
Lastly, and I feel this point is missing in a lot of arguments: ATGMs like Javelin, mines, guided mortars, etc and all but the heaviest drones are defensive and supporting weapons. For ATGMs and RPGs, these weapons exist to prevent infantry from being overrun. (And as the Russians are being reminded, they can be quite good at this.) They are not offensive weapons. That is the reason the tank remains. It's offensive.
> ATGMs like Javelin, mines, guided mortars, etc and all but the heaviest drones are defensive and supporting weapons.
Naturally they're defensive. Tanks are offensive weapons; breakthrough armor, conceived to break WW1 lines. So weapons to defend against tanks have proliferated.
The question is has this proliferation made them obsolete? Can you still effect breakthroughs when a guy with a tube can kill armor from 5+ km away? And if his man portable tank killer can't do the job he can text a missile from 50+ km with a anti-tank precision warhead so big there is no mobile armor system known to man that can withstand it. You can't have a Battle of Kursk when one M270 could theoretically kill a dozen tanks every five to ten minutes.
In a world where there is a Stugna-P "behind every blade of grass" tanks become a liability. I think they'll be scaled back to niches; there will probably always be a need for a big chunk of metal to push through and blow holes in things. Going forward though, the German Blitzkrieg model or Russia's Horde Of Armor doctrine is dead when the combatants are not greatly asymmetric.