The list of things ? Few of the teams suggested they could handle it without issue
As people have said it’s the 2 laps to fulfil the race and financial obligation’s which leaves a sour taste.
Have you ever been involved in organising an event with the public? I have, far smaller (800-1000 people a night) than an F1 event, and if I was asked to extend it for another day with less than 24 hours notice, no chance. Just event staffing alone would been a major problem.
Sure, the teams would have no problem to stay on, they can ask the staff to hang about, its their job, and sort of expected to be hiccups and flexibility is in the contract...
But lets think about everyone else..
TV - Pundits, editors, camera operators, technical staff, infrastructure, hotel bookings/catering
Circuit - Security, Marshalls, Crane operators, Helicopter pilots, medical staff, catering, car park staff, admin staff
Event - Attendee catering, Water supplies, toilets, portable power supplies, marquees, grandstand/seat hire
Local infrastructure - Road closures, diversions/etc
FIA - Support staff, technical delegates, stewards/etc
Countless other areas I have no doubt overlooked
Its a hell of a circus to mess about with at short notice, not to mention just make sure the people you need are actually available, and then if not, you need to fly in replacements/alternatives for anyone who is unable. Brundle was on his motorbike heading back to the tunnel minutes after the show ended for example. This will be the same for countless other people who have busy lives/schedules/families to attend to.
Also even if it all pans out, who pays for it all? How, credit cards/POs/credit line? Hotels/catering/etc wont just take bookings without payment at short notice! Can you secure the food/water supplies needed in less than 24 hours? If you simply fail to rebook the second medical chopper, you can't race, for example..
There is a reason why events like this take months to organise and run, they are tightly scheduled, complicated and unwieldy.