When I edit my example questions or find that example question have been edited, I haven't found any links to the revision histories.
Is there any way to view the revision histories of example questions?
Yes. There isn't a direct link to click on, but you can reconstruct the URL path to bring up the revision history for any post.
Under the example question, click the link
menu. The URL (listed at the top of your browser) will look something like this:
https://area51.stackexchange.com/proposals/2578/philosophy/2669#2669 ← the post id
That last number is the post id. You just edit the stuff around it so it looks like this:
So https://site-name/posts/####/revisions
will will bring up the revision history for any post