Treble is more about easing the process of updating the device and making it harder for an update to brick the device.
Treble requires the phone to maintain two system partitions, similar to ChromeOS. When an update comes in, it's applied to the unused system partition and then boot is switched it it.
Unfortunately, it doesn't solve the issue of drivers because, as stated above, it's simply a more safe and efficient update system. The drivers are still installed via the system update being applied to the unused partition as they were traditionally (they'd have to be, otherwise you'd have say 7.1 blobs on an 8.x systemand be unable to boot), and not coming from someplace else stored on the phone.
So sadly, other than making use of Treble's A/B partition update style, it doesn't help the issue of propreitary blobs.
