People buying these computers aren't looking for performance. They're focused on cost. There are lots of reasons why you might not need something fast.
Cost plus availability. That is why a small percentage of RPis are now being used in industrial control applications where you still need the board available in 10+ years.
My client recently ordered the remaining stock from a large supplier (several hundred) as the recent design change of the RPi4 unfortunately gets too hot and will require an enclosure/pcb redesign