Doesn't this kill the primary benefit of tabs, namely that the content is already loaded and you don't need to hit the server again?
Kind of, but if you have enough tabs the cost may become to high. I my FF set up so that tabs are suspended only after a generous time limit and have also excluded some sites so that they are never suspended. Would be nice to be able to suspend the tabs to disk instead of throwing the state away completely.
Use the great suspender extension; my friend in academia thanks me every single time we meet. And now I see them have 4 chrome windows open with each having ~20+ tabs in it!!!
For them everything happens in browser, its synced and the great suspender lets them run that monstrosity without choking their MacBook Airs