My god you still dont get it do you?
The old paradigm of mass mechanised big arrow war between heavily industrialised nations is DEAD.
We're watching live as a third-rate power, formerly thought to be first-rate, fights against another third-rate power, formerly thought to be fourth rate, and using outside support to try to move up to second-rate.
You're missing a number of key factors in your analysis here.
1. Neither side has aerospace supremacy. The Russians certainly have
more air power than the Ukrainians, but they have completely failed to suppress Ukrainian air defenses, and regularly lose airframes when they try to push into Ukrainian territory.
2. This is Russia's first time fighting with a nation large enough to stand even a shadow of a chance since literally World War II. The level of incompetence and corruption they've displayed at every level is truly staggering, and has been absolutely defining to the war. They've gone from 'completely disastrous performance' to 'mediocre performance' by giving up on trying to mimic advanced NATO tactics, and using extremely simplistic tactics instead.
3. The US has been using drones, complete air superiority, and advanced data networks
since the 90's. The big deal about the Ukrainian war, is that drones are cheap enough now that
everybody can do it, and small/cheap enough third-rate powers can afford to use them as simple suicide munitions. This is not some huge change or revolutionary, what
is a change of pace, is both sides in a conflict being able to do it to each other.
Three here is hard to over-emphasize. Since the First Gulf War, the world has been so accustomed to American military power so utterly and completely curbstomping any enemy which its politicians allow it to engage, that a lot of people didn't bother paying attention to the particular details of
how it does that. The tools we're seeing in Ukraine are not
new, what's new is seeing other people use them, and use them reciprocally.
The reason that this war is bogged down is not because of broad use of new technology never seen before.
Every bit of this technology has been used and seen before. It's bogged down because the Russians thought they were hot shit enough to pull of NATO tactics, and got their faces kicked in for their trouble. Even with that being true, the Ukrainian military started out a fraction of the Russian military's size, and even as they've rapidly mobilized, they don't have anywhere near the amount of heavy metal needed to match the Russians hardware capabilities.
And again,
neither side can use air power effectively.
If the US/NATO were involved in a conflict like this, you would see sustained, devastating SEAD operations using fifth generation aircraft, and very expensive stealthed air-to-ground missiles specifically designed to take out enemy SAM batteries. Nobody knows absolutely for certain that it would be 100% effective, but we
do know that it would be a hell of a lot more effective than what the Russians have managed, and than what the Ukrainians even remotely had the capacity to try.
Once the enemy doesn't have a single battery capable of high-altitude interception, their own aircraft are either shot out of the sky or forced to retreat to airbases hundreds of miles behind their borders,
then you try for a major combined arms offensive.
The Russians were too incompetent to do this, the Ukrainians lacked the manpower and hardware to do this, and it is
core doctrine for the US/NATO to establish these conditions before you try for a major advance.
Plus, when you can coordinate your service arms effectively like this, it prevents the enemy from having weeks and months to entrench heavily.
What we're seeing now is not some major evolution in the form of modern warfare, it's seeing what happens
when neither side has the ability to fight a modern war. There are certainly lessons to be learned, important things to note from the proliferation of drones, but unless your quote is referring to how
World War 2 style tank advances are dead, no, using mechanized forces to push thrusts into enemy territory very much is
not dead.
Not as effective as it used to be, sure, but until you can come up with a better option for a rapid drive than mechanized warfare, it isn't and won't be dead.