Indeed. Several strips of thin linen fabric were glued together in a process very similar to what we do with fiberglass. Laid in a mold, they were glued together into a semi-solid cuirass which was trimmed off and probably faced with bleached leather or linen (because the end result of all this gluing is most likely a drab mottled brown).

However, the protective nature of this armor is substantial. Each layer of linen and hard glue provides a very tough nut to crack, and remains semi-flexible. (Remember, this is glue way before the advent of plastics. It's made from animal horn or hoof, mixed with extract from fish bones).

Leather armor is also viable though, because it too is generally a couple of layers stitched together and then hardened (though not often boiled, as this provides a rigid and inflexible material that is fairly brittle... ceremonial armour, anyone.)

Today we have a rather childish understanding of body armor, I think, worsened by the fact that many of us play video or pen and paper role playing games, where armor is 'ranked' and given a rigid value structure. If you'll notice, in EB, units with linen armor are not too much worse off than those with mail, same goes for hardened leather.

The Linothorax itself went the way of the sling though. When the Romans conquered the east, they found no more use for the artisans creating this time consuming (though inexpensive) form of protection, and it passed into history as these men were employed in other crafts, the demand for their primary product slipping into the red.