I am more curious that OpenWrt doesn't set these (demux) settings. It feels a bit like looking for advice on ZFS tuning and finding out 10 years later that what you were told was completely wrong.
Where this concept gets a little unnerving is the medical industry. Imagine if your doctor did not stay on top of the evolution on medicine and technology. They would confidently perform the same actions and prescriptions they did a decade ago even if it was now know that those things were not only wrong but also wildly dangerous and ineffective.
At least with routers and ZFS we are hopefully not using those to save lives and in the example in this thread it is just tiny change among hundreds of changes that have evolved with only marginal gains.