I'd just like to chime in that some people DO have the money, time, space, and patience to keep 30+ bettas. A friend of mine had a "betta room" where she had 25+ very good sized tanks, each with a betta in it. She did a lovely job of setting them all up, she built shelves to go around the room with lighting in the tops of the shelves to shine down into the tanks. I'm not sure if I'm explaining that properly, but it was really nice.
She researched breeding for about a year before she bred them, and she only did it the one time. It was a really cool experience for her but VERY time consuming to clean all those tanks! It would always take her a full day to clean everything. It was also very heavy on her bank account... To get a decent 2.5 gallon (at least!) tank and accessories for each could come to $40-$50 per tank, depending on where you shop from. She got some decent finds at garage sales and Value Village, so if you're looking for a tank start there. But it still took quite a bit of money. Especially for the food and water conditioner!
But yeah, just saying, some people CAN do it, and do it successfully. Just not very many people. Heh. I could never do it. Partly because I already have so many animals I care for.