Deliberately pricing people out of their home & way of life is neither right nor is it going to lie well with those it affects.
I'm sure most of you will agree with me that you choose this way of life because you love it. Yes the initial out lay maybe cheaper than bricks & mortar but after that is more expensive, licence, insurance, maintenance, repairs, diesel, gas, logs/coal etc etc. I for one would be furious to be priced out of my home, way of life & social circle and would do everything in my power to push back against the system. If I asked my employer for an extra £1500 PA because my licence had doubled, what do you think they're answer would be!
Edit:
I also suspect, like Mr Khan's ULEZ scheme has devalued many cars, doubling the licence may well devalue boats...