[Marcello]

It wasn’t me who brought Leningrad up. I previously said:

They actually did. BUT they could not supply enough to prevent both mass starvation taking place in Leningrad or any hypothetical massive escalation in Afghanistan. In both circumstances being able to do something did not mean you could arbitrarily do more of it.

Emphasis added.

Note: they DID supply their limited contingent, they DID supply the DRA army and security forces AND they DID supply the afghan population under their control, Kabul included. They had to ship half million of tons of wheat for civilian consumption during a single year. There certainly was no mass starvation in Kabul, to the best of my knowledge.
HOWEVER every single source on the matter notes that they had a hard time doing all of this. Adding, say an half million of troops or a massive reconstruction program of the 40.000 km of roads in Afghanistan or similar massive efforts would have in all likelyhood broken the back of the logistical system, even as it was the Salang pass had to be run on a one way system for example.

You wrote

Mass starvation took place in Leningrad, before the Road of Life was built, not afterwards. Preventing further mass starvation was the whole point of the Road of Life, and the plan succeeded.

Then you backtracked to

Once again, that was during the first two months of it being established.

Actually it was opened in late november, as per your source. People were still dying en masse three months later, in no small part because it failed to supply the planned tonnage in December when only a portion of the 2000 tons (and still below the 1000 or so which were the bare minimum) planned by Leningrad Front for delivery that month were actually delivered. It was a incredible effort, by any standard, but you cannot use it as a proof that every logistical problem can be handwaved away.
That is what I am trying to get across.
They could do only so much and a lot of peple died because that “much” was not “enough”.

In addition, if they could supply 640,000 in Leningrad, that would be above the requirements of supply needed to carry out the operations in Afghanistan.

What are you trying to say here? They did carry out operations Afghanistan after all. Or are you trying to say that the they could post there several additional hundreds of thousands of soldiers because they were feeding a similar number of civilians in Leningrad (and some troops engaged in defensive operations)?
Do you realize how massive is the difference in supply requirements between civilians on survival rations and modern mechanized troops engaged in offensive operations? If not, please read something about it.

But let’s assume for a moment that logistics was not an issue

In addition, you have to keep in mind that the Red Army couldn't devote all of their resources to the Siege of Leningrad, like they could to the path to Kabul.

Sorry, the Red Army still could not devote all of their resources to Afghanistan,regardless of logistics, for the very same reasons it could not concentrate on Leningrad during WW2: it had others, equally or more pressing priorities. Or are you suggesting to rob Peter (the western theater military forces, the strained economy etc.) to give Paul (a useless backwater ) when Peter is obviously far more critical than Paul ? Do you realize what was happening elsewhere during the afghan war? They could not afford to throw endeless resources at a secondary problem.

Now let’s examine what you are proposing that should have been done

simply set up ambushes

Ambushing the Mujahideen? Do you realize that it was done ad nauseam?
Read the first link I posted to “The Bear went over the Mountain”. There is an entire chapter dedicated to examples of soviet troops ambushing Mujahideen. It was a standard operation.

If the leader you are supporting is unpopular, you simply switch support.

Do you know how the whole adventure started ?
That’s right, overthrowing an unpopular leader. Does the name Hafizullah Amin rings any bells?

can use tanks to escort convoys.

Bad idea. Tanks:
1)Wear the road fast
2)Wear themselves fast when used for prolonged road marches
3)Use up a lot of fuel
4)Could not often engage the enemy due to insufficient elevation of the main armament

This was practical experience. A lot of the tanks originally available with the units were sent back because they simply were found not useful and only a smaller number was needed. Which is not to say that they were never used for that purpose but they were not as useful as you seem to think.

I could go on on the other points if you are interested but really, the 90% of the things you are touting as solutions or that you seem to think were never done fall into three categories:

1)They actually were the standard tactical repertoire.
2)They were tried and did not work.
3)They were obviously unworkable.

The remaining 10% may or may not have worked but were not enough to make a difference. Find me a war where one side did 100% of what it could have conceivably done.
Really it seems to me your animosity towards Gorbachev and Breznhev is blinding you to the actual constraints the soviet leadership was operating under. Whatever you may think of them, they were not operating in a vacuum.