I have played all versions many times and have read many of the starcraft books, but I don't recall such an issue being addressed anywhere.
The obvious answer is that since they all play in the same map, so they should all use the same resources. That is, there is no option for the game designers to think otherwise.
Only thing one can do then is to try to justify this fact.
If you have played Wings of Liberty and have talked with Dr. Hansen after the Tosh missions, you would have heard her talk about the effects of those special gas and minerals that you collected and how they affect psychic abilities (or something along those lines).
I would say probably the use of the same materials by all three races is justified by two things.
- They are the common widespread useful materials in the universe. They are in every planet and every world of the universe. Since all races expand over many planets, they would develop technology or evolve so that they use the most common material around.
- If currently the crystal or gas are not as effective as those Tosh seeked, in the past they used to be and therefore they attracted the races for their properties.
I would expand the second reason a bit more based on the race. Before though, I'd like to remind you that the three races seem to be sharing psychic properties. (Wait, they call it psychic or psionic? Anyway, it's all the same). We know this because Sarah Kerrigan for example controls the zerg, Jake Ramsey had a protoss in his head (and that episode with other humans experience the Khala), and the overmind learned the location of Aiur when he touched Zeratul's mind when he killed a cerebrate.
- Terrans: Crystal and gas for terrans seem the easiest to explain. They use the crystal to build stuff and they burn gas.
- Protoss: Due to the psychic powers of the crystal and gas (at least in the past), they embed them in their structures or armor to keep them powered up (spiritually).
- Zerg: Again, due to the psychic powers of the crystal and gas, they have evolved into extracting the energy from them to speed up their growth and connection to the overmind.
On the zerg, I didn't pay quite so much attention here, but I don't recall seeing the primal zerg (in hearth of the swarm) actually gather resources either, which could mean that their use of these resources started after they left the home planet, when they expanded to other planets and where bound to the overmind.