In other words, half of their tanks aren’t much good for anything. If the gun still works, they should give them to some country somewhere as stationary howitzers, then start selling them ammo.
Well, that depends on your perspective. The Russian perspective has been shaped by their experiences in WW II. If the enemy is approaching a defended point and all you have are poorly trained troops, you put them in older tanks infantry vehicles and let them wear away the enemy forces that they can wear away. A T-55 would be pretty useless against the M1 series tanks but it will kill a Bradley IFV quite well, thank you. Remember, if you can get even a 1:2 kill ratio on defense, it may not stop the enemy, but his losses may give him pause to consider whether or not to continue the attack. Any resulting respite may be what you need to get regular troops to the area to pick up the pieces.