Though developers vastly underestimate the difficulty in cloning something as well. As someone who thought it would be trivial to clone phpbb, it’s a lot of work to reach just feature parity. Your clone isn’t even going to have users to motivate you beyond the first 0.1% of the work.

Yes, it's basically just a scaffold, but something like this could be iterated on. The challenges are around infrastructure and funding to function at scale.

I would personally rather see something that improves on the problems Reddit solves, but tries something completely new. Cloning a product is so uninteresting.