That's likely true, since DC motors need either permanent magnets or energy-wasting field coils. But motors are only a part of the energy-usage picture.

Ideally, we'd distribute "last mile" power as DC, and devices that really need AC would handle the conversion themselves. For instance, a polyphase inverter that's designed to drive a specific motor would be more efficient than a general-purpose single-phase inverter of the sort being discussed here. So even motor-drive applications could still be a net win for DC distribution.

AC gives you cheap synchronous magnet motors. These are what you find in most off the shelf power tools. But, they can;t be electrically speed varied, and don't produce max torque from a standstill (treadmills for example use DC motors for this reason).

Its not a show stopping constraint anymore - so much so that a ton of electrical appliances can happily run directly off of 200-300V DC because it just bypasses their internal rectifiers.