It's like the car business. If you're able to front the money it can be profitable. Like recently I bought an average complete 1957 Topps set cheap needed work I'll replace probably 100-125 cards or more (407 card set) for various reasons. I'll take the star cards Mantle, Clemente, Mays, Aaron, etc. in the set and get them graded based on condition of the card or buy better graded cards selling those star cards I don't use. I'll spend 3K over a year or so and then have a set I can sell for $12k or more almost doubling my money. Finding the cards for the right price is the fun part for me online bids, online sellers, card shows, they're out there.