No. It won't kill income tax. The taxes we have to pay for purchases is a lot.
Even if I have to give 0.01$ to my friend , including the fees and all I will have to pay around 0.15$.
That's a lot of fees/tax. But in the near future if this problem is solved , then it might kill income tax.
I think you are wrong because the governments are aware about bitcoin and they will adapt the tax system. This is not very difficult for them cuz everything is under their control.
No, Government cant control Income tax via bitcoins because there is no record with government about that.
What they can least do is that they will apply taxes as soon as that bitcoins are converted into Fiat.