It's a failure if most users don't prefer self custody.
Discussion
The mainstream is always a failure

It's easier to blame mainstream for the problems we have with bitcoin.
Explain please.
The fact that 90 % of humans don‘t want to take responsibility and don’t want to have the main control over their own money without a third party is debatable in your opinion?
What ‚Bitcoin-specific-problem‘ do you see here?
Self custody can be improved in different ways. With better UX, users won't even know if they are using a self custodial wallet.
nostr:nprofile1qqsvak4cr0jzaarahhn98a9602e94sa2xt8u9dnjac8cns86lzp0z0spp4mhxue69uhkyunz9e5k7tcpr9mhxue69uhhyetvv9ujuumwdae8gtnnda3kjctv9uq32amnwvaz7tmwdaehgu3wdau8gu3wv3jhvtcw9estc's trident vault is an example of innovating self custody with insurance and better security.
A supplier who feels responsible for customers' preferences runs the risk of manipulating them. For example, the notion that "It's a failure that most users don't abstain from alcohol" leads to patronizing regulation against drinking.
World was not created to be alcohol free. Bitcoin was created to avoid trusted third parties.
Use better analogy.
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