Turns out, when a major provider went down all of our users were too busy fighting their own fires. When they do notice, it's on a day when ALL of their vendors are struggling so we don't get singled out as a bad apple.
Literally 0 of your customers will notice that you are down if their own systems are also not working.
This is perfectly valid for many businesses, up to a (shockingly high) level.
If none of your customers are up to call your service, it does not matter if your service is up or down.
But it you actually NEED security, it's clearly not an option.
It is trade-off between risk and access/productivity with a cost dimension always.
Depending on your threat model you could go to typewriters /paper as some Russian department did famously few years back too.
The real sensitive customers are on oxide.
If you want deniability no one should be doing business with you.