Weight. As you burn down fuel, the plane gets lighter, so requires less fuel/energy for the remaining distance.
With a battery powered plane, the battery is just as heavy all the time. It also has less energy density. This means wayyy less range with current tech.
It's a numbers game on rocket reliability. You pay slightly more for your launch, but if it goes bang, you get a big cheque from the insurance.
For the known launchers, their reliability is pretty known, and newer (or recently exploded) launchers often give cheap/free launches while they are effectively testing things - helps make up for the pricy insurance.
The almost endless opus usage couldn't last to be fair. I assume those costs are closer to the real cost to provide the service, ouch!