It is specious to suggest that more people wouldn't be happy with a more reasonable price. It is not 'splitting the cost' if you pay for your daughter just as it is not splitting the cost when you are at the amex. You, the one with the money, pay it all. This price will actively encourage splitting the cost and people will break lockdown.
And as for the last point, the government, well Boris in particular, told everyone to go back to work if they could, re-opened schools and universities and at one point predicted everything would be almost normal by christmas. These rises are not mostly due to people breaking rules.
Re the price, even if it was a tenner, some people would still baulk at that and there would be those that get together, whatever the price, to break lockdown.
Agree re Boris as the Government have been crap at the handling of this ever since Cummings unilaterally decided he could do what he wanted. That said, there are still many people that actively try to get round the restrictions rather than take on board that avoiding contact where you can minimises the spread.