CAinPlap, I posted there the following (wating now for reviewing...):

In deed the raw material supply for GaAs could be a matter of concern - as it soon enters the market on a broad base. We have to concider 3 factors:

A: annual production of GaAs (is not fixed, can grow significantly)

B: demand: Let us estimate that the GaAs in one chip (in 40nm node) is less then 0,01g, so 100 Million Chips will make one metric ton... This is neglectible - But to produce dies the ammount will be much higher.

C: The actual situation, - Major GaAs consumption is the analog RF-chips (in all of our smart phones) and white LED (in all our screens or LED bulbs!)

Well, a lot of calculation for the specialists... But finally:
- Yes, compared to Si the recycling of GaAs will make much sense!
- We should not worry, as the existing consumers for GaAs (LED and RF chips) will be dimensions above the ammount needed for GaAs logic or memory. Like the Si for semiconductors is neglectible compared to the Si going to photovoltaic cells.