Might be worth looking at median rather than average. Or even some target percentile. My impression is that the bandwidth available to the top quartile of users has increased at a much faster rate than the bandwidth available to the third and fourth quartiles.

For example, last year I moved to a new neighborhood with a different (and wider) of internet service providers. My effective (as measured by actual, not advertised, speed) increased by two orders of magnitude at the same time that my monthly Internet service bill dropped by ~15%.

It was a particularly noticeable change for me because it made the difference between me having a pleasant experience using my company's product from home, and my company's product being simply unusable from my home.

(But don't mention that to our front-end developers or they'll just get in a huff about the modern web and people needing to get with the times. As if the lack of fiber in my [urban] neighborhood were somehow a choice that I made for myself.)