I agree, though the break-even point is way below $300/hr.
My time is valuable... not just in a monetary sense, but quality of life. I weigh the monetary difference between trading in (anywhere, not just Apple) and private sale against the amount of time and energy it will take to obtain the higher price of the private sale.
In larger communities, the effort needed is less... but in rural areas, it is quite different. I'm not hard up scrounging for money to make the purchase on a new iPad that I want to buy so maximizing top dollar isn't a high priority. I used to look at the trade-in values and think that for THAT price, I'll keep it. Except after a while I had a stack of devices that I wasn't using and became so old that I couldn't give away. ? (see my post about what to do with old iPads)
When I'm itching for a new iPad, I'll regularly take a peek at Best Buy's trade-in values. Trade-in values fluctuate, and not always lower. I haven't figured out what those values are based on or why they change the way they do, but there is usually a window where the trade-in value temporarily increases. (they sometimes offer more than what Apple offers) That's when I'll take a screenshot and head over to trade the device in.
For anyone trading in at Best Buy, be warned... they've begun to pull some shenanigans with the trade in process. Make sure that model numbers match exactly, print out the trade-in page and bring it with you. Obviously reset the iPad, and clean it thoroughly.