reason why is standard single/dual band extenders drop throughput by 50%. This happens because that have to go router---extender and then extender----devices. And they can't do both at once. So this cuts speeds in half. And this is based on the signal they're getting. So if distance/obstructions/interference already has the signal decreased, that is what gets cut it half. Add another extender and that drop is in half again (plus distance/obstruction/interference). So that 2nd extender could be running at 10-20%speed.
Its why triband extenders/mesh systems have gotten popular. They have a dedicated backhaul that helps prevent that 50% loss.
