The ultimate problem is top of the line batteries don't hold even 5% of the usable energy that an equivalent volume of fuel tank holds. And that's top of the line, very expensive batteries.
Forklifts that spend large percentages of the day not moving (and thus not using any power) and never going fast enough that aerodynamics come into consideration, are not comparable.
The idea you only need 10% of the power to cruise on level freeway is silly. That would imply a 400hp MH is only using 40hp. For comparison old VW bugs rated at something like 60hp, it's everything they can do to maintain freeway speeds. A MH is going to need several times that power.
Until you solve the battery problem it's a no go for pure electric propulsion.
Hybrid is doable but unlike passenger car operation, it doesn't work so well with an RV. Hybrid benefits are in stop and go city traffic, something most RV's avoid like the plague. RV's typical use is freeway driving where hybrids are pure IC engine driven. The big issue is they have much worse HP/weight ratios compared to passenger cars to begin with. This makes hill climbing a big issue. Regenerative brakes don't help if you can't make it to the top of the 10mile grade.
If it was viable, you would see trucking companies all switching over. There are enough trucks and they care enough about fuel consumption that it would happen if viable.
