If you don't think it's clear that the author's advocacy of PDF is a means to an end, subservient to their desire to dismantle surveillance capitalism and the duopoly that Google/Apple have on the web, I don't know where to go from here.
why don't we have both?
I think you're the one who got nerd-sniped here. 1.5 of the 13 pages in this PDF are about surveillance capitalism. The rest's about web standards.
What in the nine hells is nerd sniping?
It's when you trick a technically-minded person into jumping down a rabbit hole of a technical problem/controversy. Here it's PDF vs. HTML, but other classic nerd snipes are UTF-8 vs. anything else, "fixing" election tech, etc.
Edit: If the article _was_ all about surveillance capitalism, then it wouldn't be worth upvoting as actionable solutions are much more valuable than preaching to the choir.