You already get it, built into the ticket price. Essentially your 'insurance claim' is achieved by utilising the Conditions of Travel (NRCoT) which give you a 'get you home' (or at least home station) guarantee. Franchisees build in the cost of delay repay, and alternative travel/hotel costs, into their bids.
If you are proposing that this passenger right/benefit be withdrawn, without any recompense, I expect you will receive a large bonus check from each of the TOCS due to the windfall you have just handed them.
If insurance (compulsory or an optional extra) replaces the relevant sections of NRCoT, I expect to see a real reduction in ticket prices to a similar value.
National Express offers insurance alongside their tickets (or did).
My bank offered (unnecessary) credit card insurance alongside my rights written into the Consumer Credit Act. How did that pan out?
Today brings with it I see, (several threads already running) the usual can I /can't I expect delay repay or RRB's etc as the published timetable is revised, or entirely withdrawn (with or without good excuse depending on individual circumstances across the country). I fail to see how someone, on the last day of their holiday, can suddenly find somewhere to stay at short notice just because the advice is 'do not travel'. We are not all on train driver's salaries! I suspect any insurer would refuse to pay out anyway if you had commenced travel dis-regarding such advice.
Far better that these things be managed by a large organistion with competency, training and commercial strength rather than hundreds of individuals trying to arrange it on their own. Imagine, say, several Avanti trainloads of passengers bailing out at Milton Keynes due to 'job stopped' and them all trying to book hotels, taxis, or a few clubbing together to hire a coach to get them home. An individual passenger missing a last connection home may well prefer to make their own arrangements to suit their own preferences but hundreds and thousands, no I don't think so.