global corporate tax raiders

why are our governments not taking positive action to counter smart global corporations who are avoiding billions of dollars in tax revenues by taking advantage of international tax loopholes?

amazon, google, facebook, twitter, starbucks etc etc make a mockery of the tax systems that apply in most of their successful markets and pay little or no tax in these jurisdictions on the back of deals done with host nations (eg Ireland, Belgium) who are flattered by their attention.

politicians express platitudes and tell us that they are addressing these issues - yet nothing happens. its time that these companies accepted their social responsibilities to contribute their taxes back into the markets that generate their profits, and time that governments stopped talking about it and took co-ordinated action.