Wear on the throw-out will increase free-play. Wear on the clutch disc will decrease free-play. What actually happens in any given case depends on which is wearing most quickly.
With proper maintenance, the disc will generally see the most wear. With inadequate maintenance, the throw-out will generally see the most wear. And, either one can lead to the other.
The only thing that matters is, if regular adjustment are not made, SOMETHING will wear, and the end result will be the same - you MUST remove the engine and gearbox to repair it, regardless of which part has actually failed. And, given how much work that is, it would be insane not to replace ALL of it - clutch disc, pressure plate, throw-out, flex hose, and rebuild/replace the slave cylinder.