The browser is what it is because it's the camel designed by global committee. It's the place where competing interest groups fight one another to a standstill on a daily basis. Quite a lot of the stranger aspects aren't so much "features" as blast craters of past disasters.

For example, consider the five technologies for interactive, animated things in the browser: Java applets, ActiveX, Flash, Silverlight, and Javascript. Apart from Silverlight, which never really took off, they're all 20 years old. Only Javascript has survived the security wars; Java applets are dead, Flash gets a CVE bullet with its name on every few weeks, and ActiveX was killed long ago.

The near-death of NNTP is a story of spam cancels and cost allocation.

The browser covers all use cases and is available everywhere. That means it's necessarily horribly compromised compared to native solutions, but is an absolutely killer advantage for adoption. Incrementalism nearly always wins.

Furthermore, the unwillingness of people to pay directly for software leaves us with a continual problem of exploitative software. Everything from flashlight apps that steal your contact list to ads that steal your battery to connection-sharing apps that open you to liability for the actions of others. For the moment, we keep other people's software securely nailed shut in the browser.