Electric bikes eat consumables and components like mad. You're carrying more weight and speed, plus a mid-drive is putting way more wear on the geartrain. My Gen 3 Bosch stuff can wear through a new cassette and chain before it hits 800 km because of the small drive pinion and the extra tension and bending arc it puts the chain through.
It's just part of the cost of running one. Way cheaper than a car, but you gotta keep it fed with lots of tires, chains, gears, brake pads, rotors...