I breed for my own personal collection. Wild bettas of sexable male/female pairs are hard to get in and not many LFS stock them. My goal is to have a sustainable number of my own home-bred fish that I can then introduce new blood into by purchasing a few spare pairs.
Wild bettas are sort of a niche market, similar to killifish or apistogramma. Because only a certain pool of people are interested in them, they can be harder to sell. However, they do seem to be gaining in popularity, particularly since the behaviour of aquarium-bred wild bettas is essentially identical to that of splendens. All except my recent wild-caught purchases hand-feed from tweezers, and usually maul my fingers if I stick them in there.
You can house them in larger groups, but I have found any non-spawning fish will tend to eat the fry of your breeding pair. Also, although most wild species are not as aggresive as domesticated splendens, they will still fight, particularly the males.
My rutilans live in a large family group and because they are nearly at maturity and are due to move into a bigger tank, they are constantly sparring. The main pair (mum and dad) have just resumed spawning but I am going to separate them from their juvenile and adult offspring as I believe they are cannibalising the newborn fry.
Biggest tank I house my wilds in, is 10 gallons. I keep mostly smaller species, but I do have one adult female ideii who is roughly the same size as a macrostoma, and a trio of young unimaculata living in 10 gallon tanks and they do fine. Because our tapwater is perfect for wild bettas and because the low pH of the water in my tanks make it near impossible to hold a stable cycle, I just do 25% water changes every two days. This system has worked well for me, even in tanks where they have been growing fry.
Probably my holy grail of wilds is Betta persephone. They are almost extinct in the wild but thankfully seem to be doing well in captivity. However, my Betta rutilans will always hold a soft spot for me as they were my first foray into wilds and have just been a dream to own. Although for the first two months I never saw them and thought they had either jumped out or died haha.
Oddly enough my brownorum and rutilans males mouthbrood rather than bubblenest. It is not unknown for these species to do that, but I have yet to figure out why they chose to breed this way when my other coccina complex bettas have always bubblenested.
I have tons and tons of pictures of my wilds. Here is my persephone pair in better days. My male is extremely sick at present and so I am hoping he pulls through.

(persephone fry in quarantine/hospital tank due to an outbreak of ich)
My unimaculata. I would never recommend this species to anyone. All mine do all day is try and figure out ways to commit suicide through jumping. They have to have a towel and two glass lids over their tank at all times.
Tussyae juvies. Unfortunately poor mum upped and died so I am trying to find a replacement for her as my juvies both look very male.
My rutilans family being turds. I think there is 9-11 fish in that tank.
Tussyae spawning
Brownorum when I first got them and they were about 1/3 of the size they are now haha
Livida male who has never unfortunately had a partner and who lives as a bachelor with my tussyae males
Strohi juvies before I sold them to Aus (a member on here)
Hope that is enough info for you to process haha