Crypto 101: never let anyone have your private key. No-one who religiously followed that rule has ever had their crypto stolen.
Coins go missing from exchanges, which break the basic private key rule. People use exchanges for convenience because as clever as cryptocurrency is, it has no answer to the exchange problem.
The infrastructure of both payments for goods and services, and for storing your assets.
As of now, paying for goods and services with cryptocurrencies is relatively risky; it's hard to get recourse if you're scammed; and the standard credit card infrastructure with chargebacks and fraud protection is comparably more trustworthy.
As of now, storing cryptorcurrencies is risky. And I'm not even talking about the shady brokers/exchanges that can steal or lose their customer's money. You can store it yourself as well as you can - but, as it turns out, most people aren't that good at storing it securely, so all kinds of risks and breaches (e.g. hacking your devices to get access to your secrets) are more common than for bank accounts but, also, the consequences are more severe - if your bank account gets drained in an identity theft attack, very often these funds are recovered or compensated, not so with crypto. So again, the existing financial infrastructure with regulation, FDIC or similar insurance in case of fraud or insolvency, mandated consumer protection in case of scammed credentials - it's more trustworthy than the commonly used processes&procedures&infrastructure of crypto storage.
I don't understand you are talking about theft? like what happens to banks and jewelry stores? like what was happening every day with dollars on far west? and somehow this invalidated the cryptocurrency narrative? how?
In reality most of the exchanges and sites dealing with crypto were (and probably still are) built by absolute amateurs with no checks and balances on their apps from a security perspective. Its scary as hell that people trust those sites with their actual money.
The recent QuadrigaCX fiasco shows this very clearly. The entire exchange (one of the biggest in Canada) was somehow just running on the encrypted laptop of this one guy, and after he suddenly died in December, there is 250 million Canadian Dollars owed to 100k+ customers that nobody can recover, because the guy with the password is dead.
Because your alternative is to trust the crypto infrastructure, which is far less trustworthy.