Ethereum and Cardano are both a few years old. Eth has many projects building on its platform while Cardano barely has any. Why is that?

Same for Polkadot, and it's only a year old. Cardano does not seem to attract developers and projects. Why do you think this is?

I've heard: 1) The Haskell programming language is difficult to master or just very different than traditional programming languages. 2) Eth and Dot gave a lot of funds away to projects building on their platforms, while Cardano focused on development and peer reviewed research implementation instead. 3) Cardano does not have smart contracts yet while Eth and Dot (sort of) do. Cardano is incomplete to the point it's not worth it to build on it yet. 4) Cardano doesn't sufficiently add any improvements over Eth or other smart contract coins.

I'm wondering if any of this is true and what you think about the lack of projects building on Cardano?