They laid us all off. They had huge plans - millions of users! Then they intersected reality in KC where all people wanted was 5Mbit service and free TV... There were many, many people working to perfect the settop box for example. We got fq_codel running on the wifi, we never got anywhere on the shaper, the plan was to move 1+m units of that (horrible integrated chip the comcerto C2000 - it didn´t have coherent cache in some cases), I think they barely cracked 100k before pulling the plug on it all....
and still that box was better than what most fiber folk have delivered to date.
At least some good science was done about how ISPs really work... and published.
Too bitter. I referenced a little of that "adventure" here, in 2021... gfiber was attempting to restart with refreshing their now obsolete hardware... https://blog.cerowrt.org/post/trouble_in_paradise/
Pie's principal advantage is that it is slightly easier to implement in hardware, it's disadvantages are that it does tail drop, rather than head drop, and struggles to be stable at a target of 16ms, where codel can go down to us and targets 5ms by default. I haven't really revisited pie since the above paper was published.
COBALT in cake is a codel derivative. It is slightly tighter in some respects (hitting slow start sooner), and looser in others (it never drops the last packet in a queue, which fq_codel does.fq_codel scales to hundreds of instances and 10s of thousands of queues, still aiming for 5ms across that target, where it would be easier to essentially DOS that many instances of cake with tons of flows.
Being one of the authors of fq_codel, cake and to a small extent, LibreQos, I remain boggled after 15 years of trying, to get these simple points across..
OpenWrt depreciated pfifo_fast in favor of fq_codel in 2012, and have not looked back. It (and BQL) is ever present on all their Ethernet hardware and most of their wifi, no configuration required. It's just there.
That said many OpenWrt chips have offloads that bypass that, and while speedier and low power, tend to be over buffered.
That said, I loved the zero page on the 6502...