Let's be honest about practical knowledge for a moment:
1) Practical knowledge can only decay so far. It cannot get any lower than 0 (which gives a modest penalty to unit build costs).
2) Practical knowledge reaches diminishing returns fairly quickly.
3) More IC = more practicals in the long run.
It's not just a Soviet thing. There is simply a finite amount of practical knowledge you can get; it can only have a finite impact on your build costs.
Consider this screenshot from my infamous "Meet US build quotas by the end of the war" game:
I have never been able to reduce the price of anything by more than that. And that requires a combination of building tons of IC before the war and then spamming around 100 STR wings until V-J Day. It's a massive reduction, no doubt about that. But thanks to diminishing returns, it took years to get to that level. Most IC savings are never on par with that and by that time the war should be over.
The thing with practicals is that if you don't build any units for a couple of years, you certainly do lose practical knowledge. But the loss is not catastrophic compared to gaining 100% more IC. And construction practicals exist, too. They also boost construction research. That means that, even though the Soviets start with lousy IC techs, a few rounds of IC building will make them just as efficient as Germany or the US. The lost practicals don't end up comparing to extra IC you can use to build stuff.
Now, what about research times? Well, here's the catch. If you don't bother trying to catch up technologically until you have practical knowledge anyway, it's not big deal. Most ground units complete fairly quickly, so getting practicals in place to research stuff isn't as hard as it sounds. As for aircraft, there is that huge tech gap between basic aircraft techs in 1936 and 1939 techs, so why bother wasting precious Soviet leadership on ahead of time penalties? Especially when you can have twice as many wings as Germany ready for Barbarossa after spamming IC. Even if Germany is ahead in some aircraft tech categories, it won't offset superior numbers.
If your practicals are low to begin with (most countries in HOI3 start with low practicals), the decay from delaying unit production isn't that bad.
1) Practical knowledge can only decay so far. It cannot get any lower than 0 (which gives a modest penalty to unit build costs).
2) Practical knowledge reaches diminishing returns fairly quickly.
3) More IC = more practicals in the long run.
It's not just a Soviet thing. There is simply a finite amount of practical knowledge you can get; it can only have a finite impact on your build costs.
Consider this screenshot from my infamous "Meet US build quotas by the end of the war" game:
I have never been able to reduce the price of anything by more than that. And that requires a combination of building tons of IC before the war and then spamming around 100 STR wings until V-J Day. It's a massive reduction, no doubt about that. But thanks to diminishing returns, it took years to get to that level. Most IC savings are never on par with that and by that time the war should be over.
The thing with practicals is that if you don't build any units for a couple of years, you certainly do lose practical knowledge. But the loss is not catastrophic compared to gaining 100% more IC. And construction practicals exist, too. They also boost construction research. That means that, even though the Soviets start with lousy IC techs, a few rounds of IC building will make them just as efficient as Germany or the US. The lost practicals don't end up comparing to extra IC you can use to build stuff.
Now, what about research times? Well, here's the catch. If you don't bother trying to catch up technologically until you have practical knowledge anyway, it's not big deal. Most ground units complete fairly quickly, so getting practicals in place to research stuff isn't as hard as it sounds. As for aircraft, there is that huge tech gap between basic aircraft techs in 1936 and 1939 techs, so why bother wasting precious Soviet leadership on ahead of time penalties? Especially when you can have twice as many wings as Germany ready for Barbarossa after spamming IC. Even if Germany is ahead in some aircraft tech categories, it won't offset superior numbers.
If your practicals are low to begin with (most countries in HOI3 start with low practicals), the decay from delaying unit production isn't that bad.
