If "typical finch" means the domesticated societies, zebras or Gouldians, probably true.
Otherwise, depends on the species of softbill in question.
Peking robins are of course bigger than most finches, but a pair or group of tiny white-eyes may not need more space than waxbills or munias.
And despite what many people believe, feeding them is actually easier than properly (!) feeding finches.
Just some ready-made pellet or eggfood, fruit, worms and sugary water keeps them happy. No need for sprouting seeds, greenfood and of course no husks of seed thrown around.

Breeding them would be trickier than merely keeping them, of course. A variety of tiny live food could be required, though if you live in a green and safe area, there is a very simple way of solving this problem.
I can't comment on softbills from the American tropics though.