It's the whole East vs West conundrum regarding stocking ... *sigh*
It places like Taiwan, Japan and Singapore, many hobbiests will cram many huge monsters into what someone in the States would consider a small tank (probably due to space constraints). However the filtration and maintenance on the tank is sufficient for the fish to live healthy lives, with many hobbiests keeping fish like aros for a looong time.
In the States, tanks are bigger and more sparsely populated, but the filtration is often a small sump with bioballs and potscrubbers in it, or a cannister.
Basically ... all the above setups would work fine, it just depends on how YOU want to keep your fish.