I would not replace it with something new, but migrate it to something maintainable.
you know the mantra:
The fact that it is a core business system does not provide an excuse, it makes it even worse.
a metric fuckload of money
Is that more than an imperial fuckload?
, but he was also getting paid something like 4-5x his previous salary as a consultant to maintain the systems he used to simply because there wasn't anybody else on the planet who knew it.
Wow, that is an extremely expensive mistake. He's bound to take his final breath at the least convenient moment. In fact, the later the less convenient. If you rely on tools that much and have no control over it, you have a very dangerous business.
Nothing new. If you have a compost toilet, you will have encountered spontaneous mushroom growth on your compost pile often enough. Also edible ones, like inkcaps. There is nothing against seeding it with a known mushroom kind. When you do that for your own household, you will know what diseases you have, and you get them anyway or are already resistant to them. Also know that the compost process kills any disease over time, and most diseases within days.
But I would never add a plastic, chemically poisoned diaper to my compost pile. Most modern diapers are chemical waste and need to be processed as such.
That is a bit too simple. Lots of modern food contains so much energy that our internal alarm switches are blown off-line. Therefore, you don't feel full anymore and you keep eating. That is called Insulin resistance (see https://en.wikipedia.org/wiki/... ) It is hard to overeat on apples. It is easy to overeat on sweets.
Off course, the food industry just loves to create food that makes you keep eating, because that will also make you buy more of it. That is why even organic meat contains sugar and all kinds of syrup nowadays. The first step to a healthy life is to eat real food.
For real business purposes, though, you'd be bonkers to accept bitcoins.
Just like you must be totally out of your mind to accept just numbers made up by private companies. In other words: all modern "official" fiat currency.
Where there's a will, there's a relative.