1. it makes changing a tire more complicated, and time is money, the longer it takes to change a blown tire the higher the penalties
2. when a semi tire goes, it goes hard, as GP noted with this arrangement the cowling will probably shatter, requiring a replacement (not just a replacement tire) and the pieces taking out other tire. If the cowling does not break, it will funnel bits of tire straight into the next tires, blowing all of them.
These covers could be useful, if they were made for containment. Requires something like kevlar that can stretch and absorb the impact.
... it's usually because the company was too cheap to buy anything but retreads.
DOT HS 811 060 is the study you should Google.
Sorry, not buying it.
Also, your comment is ironically pretty dismissive.
As an expert, do you think that the sporadic time/money cost of changing a tire could offset a significant reduction in fuel cost or trip time? How expensive would a tire change have to be to outweigh, say, a (conservative) 30% reduction in fuel cost?
Electric motors are brutally simple. So first that means they break down less often, second it means they're less complicated for the mechanic to figure out what the problem is.
And that's before the straight to technical advantages. Take braking. In a normal truck you turn speed into heat by rubbing brake pads. This gradually destroys the pads, so they're a consumable. But an electric truck turns much of the speed back into electricity instead. The pads get much less wear, you replace them less often.