What I doubt is how much unique expertise those western companies have to offer to national companies. I'm not convinced the market is so big. Facts, selfish little bastards. They don't even care about your feelings.
As the example of LNG shows, this is a very rare and hard to replicate competence - no LNG project has ever been run without an oil major involved and in charge.
That requires managerial competence, technical competence (in both cases to hire and control the sub-contractors), a very strong balance sheet, and political 'survafe' (to deal with politicians locally and at home). In the long run, we're all dead. John Maynard Keynes