Political lobbying / rent seeking from special interests influence politicians to favour fossil fuel interests.
Politicians are accustomed to finding compromises between competing interests, but physical systems do not compromise.
Short election cycles provide little incentive for politicians to address long term problems.
Bold political leadership is pointless if it gets you voted out of office. Courageous politicians are routinely removed by smear campaign mobilised and funded by special interests.
Goals and timetables are little more than a way for politicians to deflect public demands for climate action. For example, Germany is about to miss its greenhouse gas emissions target by a mile.
Governments often fail, for reasons explained here:
Next: Organisational Problems