My friend does exactly this between IKEA and Ebay.
Here in Australia, IKEA does not ship (not sure if they do else where) so she buys a heap of items at the Ikea stores and flips them online. She's been doing it for years and does pretty well at it.
Here in Australia, IKEA stores are few and far between so her arbitrage is a huge value add for a lot of her customers since IKEA cannot (won't?) ship and traveling X KM's to pickup an item isn't an option for most. Personally, I'd rather buy X item from another retailer that has a product similar to the Ikea equivalent rather than use a middle man but. People really want to buy IKEA goods rather than the alternative.
I can't see how this gentleman's equivalent will stand up in the long run but till then since Walmart's goods are less unique and more importantly, much more accessible. But still he's exploiting an OK market for now.
The self help angle he's now peddling makes me suspicious that his income hasn't scaled as well as he would like now his business has grown.
He's now got 11 employee's and a much larger footprint. His business overheads would have significantly increased and dropping from $150k to $60k a year for his salary would indicate his business Net has either diminished or hasn't grown as expected.
Hence, peddling self help to generate additional income and exposure for his business.