[newton418]

Yes, there has been an increase in the number of motors used on drive trains. But, the weight constraint keeps the robots’ pushing power in check. The grippiness of the tread available to us is currently limited, and with a maximum weight of about 148 lbs, a robot’s pushing force is bounded. With a shifting gear box, and proper ratios, the 4 small CIMs allow robots to have enough torque to spin their wheels against a wall, so the motors’ power is not the limiting factor.
Sure we might be able to slip the wheels faster, but a robot must be controllable, so the speed is limited too. And with shifting gearboxes becoming more accessible, there isn’t much reason to slip your wheels at 15 ft/sec. So, although there has been a Drive System Arms Race, other physical factors keep it in check.

Also, another potential solution is to limit the number of powerful motors (motors above 100W). The 2.5” CIMs, 3” CIMs, and FP motors make up ~85% of the total motor power. If, for instance, we only had the 4 small CIMs and then many less powerful motors, teams that want to get ahead in the FIRST Arms Race would have to slap on six extra motors instead of just two FP or two large CIMs.
I don’t know about all designs, but based on my experience I don’t think many other components require the power that a solid drive system does (except, perhaps, last year’s shooters), and we have pneumatics we can use. I really like the banebot motors, because they should be powerful enough for most arm/fork lifts, yet it would take three banebot motors to equal one CIM on a drive system, which just isn’t that practical for most teams.