It’s mostly dependent on charge cycles, but Tesla has full warrantee on the battery to 70,000 miles. I’ve got 50,000 on mine and have seen no noticeable decline in battery performance. Saw a post this week where a guy had 200,000 miles on one.
I think mechanical dependability on EV’s will prove to be better than ICE vehicles. They are far simpler motors and drive trains and operate much cleaner internally. My concern on reliability is more around the electronics. These things are essentially computers with electric motors and wheels. Electronics/computer issues are must more difficult to diagnosis and fix, and tend to be expensive. I've only had one minor issue with mine that was repaired under warrantee. it I guess all cars are becoming more and more computerized, so this would also be a concern for ICE vehicles as well.
As for comparisons to the V8,
Dodge 1500 5.7l Hemi:
- RANGE: ~500 miles.
- ACCELERATION. 0-60 in 6 seconds.
- POWER: 395 hp.
- TORQUE: 410 ft-lb.
Rivian:
- RANGE: ~400 miles.
- ACCELERATION: 0-60 in 3 seconds.
- POWER: 750 hp.
- TORQUE: 829 ft-lb.