I m on the team building HadesDex, a no-KYC swap interface, so I am obviously on the self-custody side of this argument. But I would hold the position anyway: the failures that erased entire customer bases were custodial, and no insurer made those users whole.
Yes, there were a lot of failures out there, especially in the beginning of Bitcoin when the market was new, and for small companies who had not been around for very long.
Today there are many excellent companies that have been around for a long time, and have a good reputation. CoinBase is one of them, as is Binance, Robinhood, and many others. The ETFs are mostly very good since they are underwritten by big companies.
We're 17 years past MtGox, folks

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It makes no difference, whether the exchange is insured or not, walking upto the insurance company yourself is more ideal than relying on a centralized body. Unfortunately, some insurance company won't insure your crypto, because the price shift isn't under their control, so, you'd find yourself insuring fiat than crypto, dealing with an insurance company in summary means leaving the shores of cryptocurrency to a full fiat savings course or plan.
I was talking about an insured centralized custody holder e.g. CoinBase. Yes, it would be very difficult for an
individual to get in insured for a lot of reasons.
There is, however, a solution to centralized custody failure: insurance.
Oh please
I don't know how it works over there
But I know people that work in insurance company
Their job isn't really how to protect you but how to find a way to give you the least support possible.
This is true for every single human on the planet being that does work for another human being for money. And yet, you buy your breakfast from a vendor who is "just in it for the money".
Maybe you want to live like the Unabomber, but 99.9% of the world's people living in developed countries do not.

Of course if you do, then why do you dare use something as dangerous and reliant on others as...
the internet?

If you don't trust anybody, you should get off the internet because there are literally thousands of companies that are involved in making it work to the point where Bitcoin actually works.
Don't get me wrong, I understand that there are countries out there that lack the infrastructure that we have in developed countries, and then this discussion is totally different. But today most of Bitcoin's market value is based on mainstream consumer investors who live in developed countries. Take that money away and Bitcoin falls by 99%.
There's no "perfect" solution, but the very closest thing to it that humans have created thus far is a CEX that is insured by a strong insuring entity.
Good luck convincing FTX customers about this.
For every negative high-profile example of an old CEX that went down, there are a thousand cases of people who used self-custody and lost everything. And in some cases, they not only lost their Bitcoin, they lost... their lives.