Very good overview of the preload issue from Shubhie. This bit in particular is important to take to heart, I think:
Preload can be avoided in many cases, with alternative strategies such as inlining of critical CSS and inlining font-css.
Most of the time, preload gets used as a (not particularly efficient) band-aid for an underlying issue that is probably better solved in other ways.
Also, this is probably a personal hang-up, but whenever someone from the Chrome team shares a Google Doc full of interesting research and ideas (which is super often) I always feel a little anxiety. I just don’t trust these docs to stick around as long as a blog post.