Indeed. I've often thought that such high-latency mix-nets (with their potentially superior resistance to traffic analysis) would be a nice complement to low-latency networks like Tor.

Have a look at Katzenpost. They are trying to build a modern, high-latency, mix network.

https://katzenpost.mixnetworks.org/

I2P provides cover traffic. I believe GNUnet can also be configured to use a certain amount of cover traffic.

The downside is that browsing the web on a service like that sucks ass. Tor trades off some security for a basic level of user experience.

Sadly, modern web design makes stuff like WWWoffle less useful than it used to be. Plus it's difficult to set up fully anonymous services on the far side of the link, I mean you're using Tor for a reason, and leaving breadcrumbs on the far side of the network is risky.

Using TBB has gotten much better over the past few years, often you can stream YouTube without much issue.