I believe the max number per person depends on time, space, money and mental stability. If someone has the room to proper care for large numbers, never struggles to give them what they need financially, has the time and system for regular water changes and has bettas for the pure companionship and not to collect and show off... Then good for them! I'm at a personal limit. Financially I can handle it, space and time I cannot handle more. With kids and other pets, I'm non stop. But I have time for a personal life and I don't have my bettas to compete you people on here and they don't replace human interaction. But if I add anymore, I'm going to tilter on the fence on proper care and such. I personally wouldn't want that many bettas and would not be telling some random person at the pet store how many I have LOL My LPS asked how many I have now, and they were shocked when I said 6 boys and 5 girls. I should tell them I have 99 and see what they say!!
And I agree that breeders shouldn't be classified in this. Breeders don't keep every baby they produce. Collectors do.