I got a say, though I have never played anything other than AArevised, and earlier addtions, (including expansions), people always did buy all tanks. But when tanks defended on a 2, and cost 3, buying all infantry swamped the tanks. I never bought all men with the guys I used to play regualary with, but just enough not to give it away. I was amazed they never realized the advantage of buying all men versus tanks. I always bought just enough men to not make it obvious. I have been playing for over 25 years. When they made tanks defend at a 3 on revised it became a close battle, but with the addition of artillery, again unless you had to travel far and fast, infantry and artillery is far superior in strength. It always has been, so I curious what game was it advantageous to do all tanks.
In World at WAr (Expansion), since you can improve factories to produce 2 tanks per turn at a $1 reduce price, those became the only tanks I would ever buy.
Looking at some of the maps like AA40, being so big in terms of spaces it might make sense. But tanks costing now $6, the need for speed really must overcome the advantage of fire power. If I have $42, I would much rather have 6 men and 6 artillery versus 7 tanks. Its a no brainer.