I could be wrong and perhaps in his current Ebay Auctions, at least 50% of them are selling undervalued from what he paid for it (not including his time to get them signed, if that’s his niche). I asked in a previous comment but it was disregarded.
Someone that sells Pokemon cards 300% what they paid for it so they can support their hobby addiction for boosters openings/etc is 1) profit motive on their cards they sell 2) perhaps overspent on cards that do not increase value, but nonetheless 3) they have profited and scurried away the profits.
I’m just saying I buy cards that I perceive will go up in value and I push for that idea and don’t care if people think I’m a ‘flipper’ (weird negative connotation) when I’m more so a collector. I expect others response to be different because there are some big spenders that pay whatever to acquire the card then and kudos to them.