[tjoff]

The network stack isn't written in javascript.

The slowness of the web will not get any worse by moving the network stack to userspace. Guaranteed.

[dijit]

You have the entire body of computer science research around microkernels against you here.

What has changed?

[cogman10]

CPUs got faster, memory got larger, compilers got better.

Microkernels aren't a dead idea and they are even making their way into consumer electronics. (see Zircon).

In fact, even newer oses are backing into microkernels. Windows adopted similar microkernel concepts in Vista with the HAL. Android adopted a HAL with project treble in android P.

The steady march of modern OSes has been moving driver logic out of kernel space and into user space.