[habitue]

It's true we don't build planes like birds. But we understand how bird wings work, and we understand why we don't design planes like bird wings.

We don't have the same kind of understanding of how brains learn, so the comparison is not quite right.

When we understand how to build things that learn like brains, we'll be in a better position to say things like "Ok this is strictly worse than backprop, let's stick with backprop" or "Actually, this is better than backprop because X", (or, more likely, there are things we can use from both). Until we have that understanding it's silly to stop trying to understand how the brain does things.

That being said, nobody is going to stop working on backprop, and no one is going to stop working on understanding biological mechanisms . Research works by a bunch of people investigating different avenues simultaneously.