How businesses end up here
Nobody sets out to lose track. It accumulates, and every step was reasonable at the time.
The estate was built by different people
A friend registered the domain. A web agency built the site and pointed the DNS. An office manager set up the email. Each person did their bit properly and none of them wrote anything down, because they each only held one piece.
Things were registered to individuals
The domain sits in a personal account with a personal card on file. The analytics belong to someone's Gmail. When that person moves on, the business does not lose the service immediately, which is precisely the problem: it fails silently, months later, at renewal.
A provider relationship ended badly
Or just ended. Handover was verbal, or never happened. The business is still live but nobody has the keys, and the previous provider has no obligation and no incentive to answer the phone.
Nothing broke for years
Which is genuinely the most common version. Everything works, so nobody looks. The problem is only discovered on the day something needs to change, and by then it is urgent.