yeah daveedka, i'm just so tired of those bettas in a bowl is cruel threads...the worst ones are the ones with online petitions. pleaaaase. enough already.
alpha-- i think you may be on to something...the fact that males cannot be kept together forces the keeping of them in smaller quarters in shops and among breeders. these kinds of setups would then undoubtedly follow into the home hobbyist's fishkeeping practice. this is perhaps a prime reason bettas are kept in small tanks. i like this idea. yes, other gouramis fight, too, but none have the reputation of betta splendens. this, more than any other idea so far, i think begins to explain why it's considered okay for bettas to be kept in small tanks and not other small labyrinth fish.
yonder-- no good hobbyist would recommend a goldfish for a 1g bowl. many have recommended bettas. end of argument there.
i guess there isn't a way to test this that wouldn't be risking the life of a dwarf gourami. puma seems to think that they are more susceptible to dropsy and other conditions via poor tank conditions and temperature, and this may well be true, but there really is no way to test this without trying it. i'm not sure this is so, however. as i said earlier, most sites seem to suggest dwarves can tolerate cooler temps than bettas. also, i've had that quarrantined blue gourami (as mentioned earlier) in an unheated eclipse and it appears as healthy as ever (minus the parasite that landed it there in the first place that won't go away, of course)...
i'm theorizing that one could keep a dwarf in a bowl as successfully as one could keep a betta. yes, temperature must be above 70 (minimum). yes, frequent water changes are necessary to maintain fairly clean water. but this is the case for a reasonably healthy betta, as well, so i can't buy that dwarves are significantly more susceptible than bettas. i'm certainly open to convincing, but that's my hypothesis for now.