It will not be very many years before tech gets to where we can move the blocksize up.
So I think it is still worth talking about.
-Currently I am mining on a 32thread 16 core CPU I bought for $700. In a number of years 16 core cellphone processors will be a thing. (Not for mining for the most part, but for all the hashing done to validate things quicly enough)
-$400 will get you a 16T hard drive today.
-5G has Terabyte speeds at low latency WITHOUT WIRES.
For reference, the RPi 4 is based on the ARM-Cortex A72 which is from 2014. The Raspberry Pi computers are not designed to be bleeding edge and they are (I believe) run with a small technical team which means it takes time for them to get to market. Also, I'm not sure how much it's changed but I seem to recall they had trouble getting certain technical specs from the manufacturers.
As I have said the whole "must be runable on a Pi" ethos is misguided IMHO.
But there needs to be SOME minimum hardware requirement target, and though I think the Pi is too low, I would rather have too low than too high. At least it's the Pi4.