It's an effective strategy for the most efficient game play. But alterations can be done.
The point of the 30% armor 70% range ratio (which your vehicle layout is incorrect there) is that you will ONLY take battles that are extremely advantageous to you. IT's essentially the "perfect" set up for if you yourself are perfect. How often does this ACTUALLY happen? Not very. The ratio was made so that the player should almost always be 3-1 overpowering their enemy, or using a nuke/spy to compensate.
Damage is actually very effective. The problem is that they aren't efficient (and we all like efficiency). In a 50-50% armor to damage ratio, damage units can devastate through just about any army of the same size. The issue becomes that you are essentially making a suicide run of it. It can decimate an army slightly bigger than it. You'll lose, but they won't be functioning very well either. Of course, if the enemy succeeds in a trap or nuking your army, you'll take devastating losses with no real payout for your mistake as their ranged units will rip through your army and you will barely if even scratch theirs.
But if you KNOW you'll be switching your build later in the era, it's great to start with 50-50 damage builds. You'll slowly chip away and lower your overhead as you switch over, and you have no real issue suiciding your "fake army" when the time to change comes (and hopefully you're ready at this point to switch over with a powerful ranged army).
And if you don't end up doing a suicide run, they are fantastic spam for wars to add into the mix of your normal spam bombs
But overall, it's all about how you utilize your units. If you are diligent enough, a team could win with a 50-50 damage build (especially if they work on getting R4 damage units). Once again, it's not an "efficient" build as it promotes heavy loses due to their lack of a 1st strike.
The mix builds that you listed could do great in all honesty. In a flat out even fight in terms of unit count, the mix build will do just fine. I believe they'd even win against the range build (30% armor 70% range) in most cases, but I'm not going to play around with that right now as I don't feel like putting them in the simulator.
It all comes down to how you play and how lucky you are. Even if you got the drop on an enemy in a 2 to 1 fight, if you went in with all conc inf and the enemy was a conc tank build, you'll still lose.
