"That total of font files seems improbably high to me"
Sorry you don't like it. I think it speaks of an under-nourished appreciation for the extensive reach of fonts in the world. But I can rephrase the question until your number fits — how many fonts could possible replaced by libre fonts, 32,456 font files.
...if you used a browser that just uses the default fonts and ignores everything else, you can remain unaffected by anyone else's preferences, ever. Surely there are going to be hundreds of sites, perhaps 1,000s in the future, with text choices, of both size and style, you don't like/can't read/are not adjustable to.
How do you live with all that print in the world where there is no way out?