Going slightly into the realms of speculation here, but hopefully sufficiently on topic...
What seems to be consistently clear from posts is that the ordinary public weren't receiving much or clear "what do I do next" information. I imagine this can't be generated bespoke between every impacted station pair in the moment as the resource won't exist, but a software solution does seem possible. LNER already uses pre-prepared alternative journey maps, which seem like a basic implementation, but I wonder if something more advanced is possible. It doesn't seem beyond the realms of possibility for you to tell a system that area X or stations Y are unavailable and for it then to be able to generate a "next steps" plan between any given station pair - be that "take alternative train to X then change" or "take taxi from this station to train at Y" or "take taxi from this station to destination".
Taxi (used in the broadest common sense to include private hire and Uber) probably should have a standardised way of being paid in advance. Whether that be issuing vouchers through a self service mechanism, by staff at staffed stations or by staff using a B2B app to summon them in bulk pre-paid. I accept there would be capacity issues, there probably then needs to be a switch to hotels at a certain time of night, that's also doable through B2B booking services.
In the absolute worst cases, we're going to have to acknowledge that there's still some risk that all of the above will result in people still unable to complete their journey at 10pm or some other unsuitably late time at night. I don't want my ticket price increasing to reduce that risk to near zero, it's not proportionate. I think a sensible amount of risk should fall to the public, I think that should include either being prepared to be stuck on your route or having access to a two-digit or possibly low three-digit amount of cash that will get you your own taxi or hotel and be reimbursed in a timescale of about a fortnight.