How much real-world range should I expect versus the advertised miles?

Verified-purchase reviewers and r/ebikes commenters consistently report real-world range well below the headline numbers, especially on throttle-only riding. A bike advertised at 50-65 miles often delivers closer to 20-40 miles depending on rider weight, terrain, and assist level. Pedal-assist mode stretches range significantly compared to pure-electric throttle use.