Actually I remember reading articles in Soldier of Fortune about how by the mid 1980s before Stinger had been introduced that the Muj were losing and the effective use of heliborne troops to cut off and intercept muj groups as well as take out their transport routes had gotten to the point of being effective.
the introduction of Stinger and also other systems less talked about like Milan ATGMs changed the way the Soviet fought... they turned to artillery more and their raids got less discriminant.
I love the irony though... at the time the western press derided Soviet tactics of bombing villages where muj forces were found and could not be dislodged easily.... I see on the program made by Ross Kemp that the west will happily drop heavy bombs on Afghan villages when it suits them too.
There are often comparisons with Vietnam, but that is rubbish. Vietnam was an Asian country first ruled by France, then Japan took it and then France came back. the similarity with Afghanistan was that most villagers didn't know what democracy was and really didn't care much.
the Vietnamese didn't fight for the Soviet Union... they fought to first get the French out, then the Americans and the corrupt south vietnamese.
In afghanistan the Kabul leadership ruled Kabul and most of the country carried on in spite of who was in power.
The Soviets invaded Afghanistan because the CIA moved from Iran to Afghanistan to set up stations there... which the Soviets could not tollerate. Western claims they wanted warm water ports are ridiculous... they would have to invade Pakistan to do that.
Had the US just left Afghanistan the women of Afghanistan would be properly educated, they would be able to have jobs, and vote. There would be functioning infrastructure and a much better standard of living and the country side would be much safer.
A lot of the mineral wealth of the country could probably be exploited now with perhaps a new gold rush and rushes for other valuable minerals and the country would be in a much better position.
Instead all that money and effort was used to buy weapons and ammo and to kill and destroy and several generations of Afghans don't know what peace is.
No Afghan SSR then
There was no interest in incorporating Afghanistan into the Soviet Union... they just wanted a friendly neighbour that would say no to US bases.
It is impossible for anyone to achieve strategic victory in Afghanistan.
In terms of occupation if you want to take their country from them then you are wasting your time... if you go there and build schools and set up water supplies and electricity and don't have a super power and other rich countries undermining your efforts, then you could work wonders in terms of improving things for the people of Afghanistan.
the main problem is that with money comes corruption... all the money the west spent in Afghanistan is ending up in contractors pockets...