My guess is that the cited problems are almost completely the fault of bufferbloat at or near (on the ISP side) the home router level. Pretty much all consumer

My guess is that the cited problems are almost completely the fault of bufferbloat at or near (on the ISP side) the home router level. Pretty much all consumer hardware in existence seems to be configured with way too high buffer sizes. Switching to fiber might help somewhat though, because a higher data rate translates the same number of bytes of packet queue into a shorter actual packet delay. So it slightly mitigates the pain of bufferbloat (at least until people start configuring the buffers to be even larger to "optimize for our faster networks").