We can't it be a browser-integrated feature? That we can store keys, have them sign messages and e.g. unlock the signature function through e.g. a hardware wallet or a master password?
.. Because major browsers will need to integrate it and they haven't. You can build things yourself more easily than you can convince say chrome to build something (which is the whole point of extensions, really). What you seem to be asking is just metamask to be integrated directly into chrome, which is a nice ask but not done to the right people (ask google/firefox) and its lack does not turn web3 into a 'Stupid Idea'.
There's a lot of extension functionality I'd like straight in the browser itself but it's not the extension's fault that browser devs haven't included it.
Good UX isn't security, MM and Infuria are owned by the same person (very centralized), you can't change your secret phrase, sentry.js doesn't secure a react app very well at all... etc. etc. etc. I'm not a hater (actually I'm a user), but I am pointing out a wide variety of issues that should be publicly discussed.
They were uploading significant details of failed transactions to Segment. If that ever happened to you, they have a connection of a wallet address to other personal details.