The challenge is any definition of capacity (speed) requirements is only a point-in-time gauge of sufficiency given the mix of apps popular at the time & any such point-in-time gauge will look silly in retrospect. ;-) If I were a policy-maker in this space I would "inflation-adjust" the speeds for the future. In order to adapt to recent changes in user behavior and applications, I'd do that on a trailing 2-year basis (not too short nor too long a timeframe) and update the future-need forecast annually. And CAGR could be derived from a sample across multiple networks or countries. In practice, that would mean looking at the CAGR for the last 2 years for US and DS and then projecting that growth rate into future years. So if you say 35% CAGR for both US and DS and project out the commonplace need/usage then 100 Mbps / 10 Mbps becomes as follows below. If some new apps emerge that start driving something like US at a higher CAGR then future years automatically get adjusted on an annual basis.
So what happens if the Next Big Thing requires a lot of upstream? It's always been sort of a self-fulfilling prophesy that people won't use a lot of upstream because there isn't enough upstream. The pandemic pretty much blew that away with video conferencing, etc.
That shows up as increased user demand (usage), which means that the CAGR will rise and get factored into future year projections. So if the CAGR for US goes from 35% to 75% then when you annually update the requirement and project that CAGR forward, you will have higher future BB numbers that grows the US requirement at a faster rate. That is I think the benefit to a system that uses trailing demand to forecast forward with growing year-over-year BB numbers. You can debate whether 2-year trailing CAGR is better than 1-year, but conceptually the idea is that future BB numbers should be 'indexed to inflation' - so grow year-over-year based on past actual growth rates rather than a once-a-decade BB definition that is not driven by actual demand and is arguably theoretical. Jason