Can Gallium Arsenide replace Silicon, Germanium and Carbon as semiconductors in the future?.
Well, Gallium Arsenide is being used in some applications as a replacement for Si based products. But it's cost has kept it from becoming more universal.
But, it doesn't seem to have been a very universal movement in design of all silicon based products.
As indicated in the above link, it doesn't seem to have fulfilled the expectations that seemed forthcoming back in the 1990s when it was introduced into some application areas.
It is a subject of much consideration among development activities and laboratories working in advanced semiconductor areas.
Unfortunately, I am not an expert in this area of material physics so I don't expect that I can offer further assistance to you on the matter.