The likelihood of facing considerable losses conspires with the fact that, point for point, your close combat frames won't be any cheaper than the opponent's frames (more likely quite the opposite).
On a frame per frame basis, this is generally true, but, due to statistical issues not worth getting into at this time, close combat armies will be able to offset their opponent's points spent on ranged weaponry by keeping their infantry AR's around zero (-1 to +2). Two quick reasons for this are:
-heavy armor tends to be maximized if you advance slowly from cover to cover, in which case it will make the odds on may shots drop off of the linear curve pretty quickly. If you charge straight at someone, however, the enemy's stationary bonus will often offset your armor.
-weak armor is terrible against suppression fire or AOE, two of the main tactics against close combat or "swarm" armies.
Another somewhat statistical point is that it will generally be worth spending the points to get a high reflex and multiple HTH dice. This will maximize your offnese to defense ratio. Also, it will allow relatively few close combat specialists to take out a fairly large enemy unit that has not spent such points.
Finally, tactical advantages can be taken that allow you to get the most tournament bang for the buck when using a close combat army.
In the end, close combat armies will still only be viable if they have some way to circumvent being forced to run into fire lanes. This means investing some points in indirect support fire, flight ability, or a few troops with ranged capability. If you look at most CC armies out there (40K, WZ, even SST), this tends to be the case for all of them.
-Demian
whose favorite Defiance force is the Meraxilla, which are likely the most point-for-point CC heavy of the army lists.