They might not be the answer but they've helped my mum, who has emphysema, cut down drastically
on the real thing- more so than all the patches, gums and other whatnots that she's had a go at. She says that while she has an e-cig, she isn't bothered about smoking a 'real' one. She has had periods of total abstinence but because she has had severe depression/ anxiety, nicotine is her 'crutch.
I know that she is only one case in point, however.
All the same, it's not in the government's interest to promote e-cigs for the very reason you give above...unless they tried taxing the e-cig, of course (I wouldn't put it past them, either!).