UK tax inefficiency

Why do we still have TV licences? Why not just increase income tax or increase VAT on TVs, PCs, mobiles and phones and save all that admin cost? Same applies to road fund tax: why not just put up fuel duty? Again, less admin, no evasion.   Likewise the winter fuel payment for all people over 60 in the UK: the taxman knows how old each of us is, so why not just increase the tax free allowance on income tax if you are over 60?