it's an eternal battle. every once in a while we pass legislation to try and reign in corporate power. like for example the anti trust act in the early 1900s
the issue is that public attention is temporary. eventually we move on to the next crisis and people forget. grow complacent.
corporate interest, however, is eternal. it's persistent and never gives up. it keeps pushing, infallibly, in order to weaken the structures meant to reign in their power. whether by legislation/policy (AT&T and friends unilaterally killing Net Neutrality some years back, Disney signing into law expansion of copyright, etc) or through more subtle methods (buying politicians and getting people into positions of power that have no intention of enforcing the laws)
this is inevitably what happens with every democracy. eventually the vigilance fails and the structures of power are hijacked by opportunists.
although having said all that, I don't think greed had much to do with the inflation we saw. Sure, some companies took advantage and raised prices more than they needed to just to inflate that extra juicy profit margin.
but realistically we're headed to war and war means massive government spending which means inflation