[HPsquared]

Gas turbine engines have critical components which can have gradual failure (fatigue particularly, and creep) which need regular inspection to catch small defects before they grow to critical size. They also have large numbers of high-temperature, stressed components.

Electric motors are generally much simpler in construction and wouldn't need nearly as much mechanical inspection.

The difficult/expensive part is the battery, but that's going to have more onboard condition monitoring and will be simply replaced periodically, not subject to regular teardown inspections. The cost of ongoing battery replacements might be significant, though.