The notion that drones have ended mechanized assaults has always been as ridiculous as the notion that modern anti-tank missiles have negated the usefulness of the tank.

Both impressions seem to have come about through a combination of two factors; the media tendency to emphasize the new and the strange, and to eschatologize everything into it's most extreme form, and the fact that one of the two sides in this conflict is a very poorly run military which has proven shockingly slow to adapt when presented with new and unexpected threats.

Western anti-tank missiles slaughtered Russian tanks in the early stages of the war partly because those were the exact tanks they were designed to defeat, but mostly because the Russians used their tanks very poorly, often with little to no infantry protection meant to defeat such an attack.

Ukrainian drones have been slaughtering Russian armored and foot assaults for very similar reasons. The Russians do not sufficiently plan their attacks, and they move units haphazardly and without proper support. This means that they lack the eyes or the guns needed to spot and shoot down an incoming drone.

For all the things drones can do, there's plenty they cannot. An FPV drone is much slower than a missile or launched grenade. It is much more susceptible to jamming, hacking and interception. And it still relies quite heavily on line of sight to the operator under most circumstances. Militaries already have to deal with threats like artillery, ambush strikes, beyond visual range weapon systems, and so on. Drones are a new dimension in that threat model, but it is still, fundamentally, the same threat model. The basic principles of warfare apply, they just need to be applied with forethought and understanding.