This may depend on jurisdiction. Joint accounts were not frozen in my case. A death certificate was only required to remove the deceased party from the accounts.

What happens if your partner sets up your home network and TV subscriptions and their email account is locked because you're not the account holder.

In my case I was able to present the death certificate to the providers and the accounts were quickly closed, with the appropriate billing and hardware returns. It was no more inconvenient than a normal return.

I was fortunate. The deceased planned ahead and did all of the things I haven't done: arranging a funeral and burial, keeping their will up to date, writing down their usernames/passwords, and making the appropriate joint bank accounts.

This is repeated across every single aspect of modern life. Your robot vacuum cleaner is linked to a single person, as are your IoT lightbulbs. It's absurd.

My experience was with established services in mature sectors: they have procedures for dealing with deceased customers' accounts. It was relatively convenient, even at a really shitty time.

None of that is easy, convenient or handled.

Why not?

Newer services don't have that institutional experience. They haven't existed long enough. But they're starting to: Facebook has the concept of deceased users. As time goes on, more "new" services will as well.