If you ask a tanker what would he prefer: t55, t62, t72, t80 or t90 he would without a doubt say t80. Its a fluent tank: turbines allow for a smooth ride and more accuracy on the move, more fuel economy, speed, acceleration, better maneuverability and turning etc etc. Its called a flying tank for a reason: the acceleration allows to dodge or deflect incoming rounds jumping to the side all thx to the engine. Also the sound is not as loud. The modern Russia is behind the ancient USSR in many ways. Maybe thats why turbines for tanks arent produced but without a doubt they rule. USSR could produce first turbine tank - Russia cant. USSR could launch space drones - Russia cant ect. It probably has to do with it. T80 U M1 is the best tank ever. USSR was best at tanks stereotypically its because of quantity to put it simple. But in fact its exactly because of the quality of the takns such as t64 and t80 which for the first time could easily defeat much much heavier opposition.
The T-80 was bunged for a variety of reasons:
the factory that makes them is in now modern day Ukraine meaning that licensing to make them would be though the roof.
The Soviets did not have a very good time using T-80's in the wars they we're introduced, although this was a more lack-of-training then bad design, it did stick on with the Soviet commanders
Turbines are horribly expensive, expensive to make, expensive to maintain, expensive to run. Russia does not have the budget that it used to (It's not even in the top 10 for military spending anymore), and simple diesel engines are just so much easier.
and probably more but that's all I can think of right now. Now back on topic!
auto loaders have a few advantages:
You require less crew members, meaning less salary needed and more trained members for tanks!
an auto loader is much more consistent, only a highly trained crew member can outperform an autoloader, and even then factors such as fatigue, injures (such as battle injuries, RSI, or sickness) and human mistakes meant that manual loaders struggle to find a consistent rate in which to beat auto loaders.
Less crew members meant a smaller tank, and a smaller tank use less fuel and we're harder to hit!
There we're disadvantages:
cheap auto loaders required you to move (such as the ones found on early models and cheap export T-72s) your gun in order for them to work, meaning that you had to re-align your cross hairs after every shot you took. this is probably why early models of Soviet tanks have such bad accuracy in Wargame. later models did address this though!
Autoloaders (at least early versions) were more vulnerable to enemy fire due to the fact that they had to convey shells from the hull to the cannon, meaning a direct hit there could cause a catastrophic pre-detination. Early Chinese tanks we're the greatest offenders with one model (I think
it's wither the type 59 or type 62) actually stored all the shells in the cannon, making them much faster to reload and less prone to jamming, but became extremely vulnerable as any shell or missile that hit the cannon would cause a devastating cook off!
So there are advantages and disadvantages, each country has their own reason for their choices and they are usually completely just with nether side being wrong. It's really up to the individual to decide whether or not the pros outweigh the cons.