Brilliant! The problem with waiting until the crap hits the fan is exactly as you outlined. Everyone goes out and buys at the same time causing disruptions. This is why beginning in February 2020, after realizing a potential lab-made bioweapon had just been released, I began to buy extra toilet every time I did groceries. Only few were paying attention at the time so there was no rush. Little by little, I amassed reserves of toilet paper and other goods, and by the time the panic set in early march, I was already prepared. All I had to do was sit back and watch everyone run around with their hair on fire before getting locked in.
I think a few more pandemics will hit in our lifetime, and we will all do exactly the same as before x 1000. So this service is actually not a bad idea. I already have enough razors to last me several apocalypses thanks to a subscription service.