Yeah, I’ve run that sim many times - in fact that question is one of the main reasons I built my sim. However, that sim doesn’t tell everything - the speed of armor is worth maybe more than you think.
Yes, I agree, 8 Art in Ukraine add more punch to the assault on Caucasus than 7 Tanks. However, Those 7 tanks can add their punch to that assault while sitting in Eastern Europe, where they also:
a) are defending Eastern Europe
b) are in striking distance of every single European territory.
So if suddenly the allies land in WE, your 8 artillery in Ukraine are worthless, while the armor allows you to respond. Which in turn may dissuade the attack in the first place. The trouble with building artillery first until the range of Tanks is “useful” is that you’ll have less tanks in the end. There’s nothing like a hammer of 30 tanks and infantry everywhere to keep the allies at a respectful distance.
I could see for Russia though that they would be more worthwhile. Still, defensively you can’t beat infantry, which Russia can build to reinforce territories taken by the UK/US before Germany gets to counterattack.