The long and short of it is :
Pharma and Tobacco have lost lots of ground (and by ground I mean money) by passing over ecigs as a fad - they have very deep pockets and can influence ANY legislative decision if they want to.
Governments have been caught napping and are losing tons of tax revenue from smoking, that and the bonus they get from the populous dying earlier (less pensions money needed) and the obvious kickbacks they get from Pharma who peddle their anti-smoking wares and drugs to treat smoking related illnesses.
All three corrupt parties are looking to make their money again.
How they get there in the short term is to try and stifle the industry, try and make it crumble before legislation, reduce uptake through fear that things explode, poison or are harmful in some way (media spin 101). They then go behind closed doors with their billions in revenue and concoct a product that they can sell as 'safe' in it's place - all the while hoping the industry just burns out in it's current guise so they can clean up the market.
They then finance a back door in which the current regulations no longer apply (med regs or just plain brown paper bag technique)
It is ALL about money, not at all about health and disheartening to realise how much of a cash cow the human being truly is. If the Matrix film hadn't been released already you would swear you wer in it.