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.
While most adults need between 7 and 8 hours of sleep, some need as few as 6 and some as many as 9 hours of sleep each night. The general rule is that the amount of sleep a person needs is the amount that allows him/her to feel fully refreshed and alert all day long.