1.
Gear Drive - It's durable, easy to maintain, and, when done correctly, can push basically any robot on the field.
2. Control of Position - In my opinion, the fundamental objective of a drive system is to allow you to get to where you need to go on the playing field and stay there as long as you need to. Depending on the game, this could mean that your drive might be fast and maneuverable so you can avoid object or other robots, it might mean your drive is slower but strong enough to allow you to defend opponents or prevent opponents from defending you, or it might mean your drive needs to do a little of both depending on the situation during the match and you use a two speed shifter or some other mechanism to achieve this goal.
3. A robot is only effective if it can get to where it needs to be on a playing field. You could have the most accurate shooter, or the most effective arm, but if your opponents can hold you on the other side of the field from the goal, they probably won't do you any good. I've seen matches, and even entire regionals that were won simply by having a robot on an alliance that could stay between an opposing robot and the goal, even if blocking was the only thing that robot could do.
4. The "Drive Train War" was mostly the effect of this years field being so open (no obstacles), by comparison, the games of the past several years have had field obstacles and defense rules that made such drive systems impractical/unnecessary.
Strong drive systems are nothing new, 6CIM drives were possible as far back as 2006 (maybe even before that) before bumpers were mandated or even common, they're simply easier to build in recent years due to the availability and relative low cost of high quality COTS gearboxes. Drivetrains will of course, continuously improve, and teams need to be able to adapt to handle the different play styles that come with better systems each year just as they would with any other part of an FRC challenge.