That's not quite the range of the Phantom 3 Professional, which managed 2,500 feet without issue, but it's better than the 1,000 feet I got with the Phantom 3 Standard in open space and the 400 feet it managed in suburbia.
Medical specialists with a public voice like Dr. Oz should absolutely be encouraging people who are sleepy to sleep more. However, arbitrarily applying eight hours to everyone is actually harming people who simply need less sleep, or those who actually need more than eight hours.
In general, the average healthy adult needs 7 to 9 hours of sleep per night. Experiments have demonstrated that the average amount of sleep needed to avoid detrimental effects on daytime function is about 8 hours and 10 minutes. It is recommended that adults beyond age 65 may need less sleep, averaging 7 to 8 hours instead. If excess time is spent in bed, insomnia will result.