(1) drivechain is already associated with bitcoin. Merge mining and sidechains scaling has been tied to bitcoin brand since Blockstream released their white paper on bitcoin sidechains in 2014.
Regarding point (2) that’s the purpose of sidechains. Keep mainchain unchanged and scale via sidechains.
(3) maybe if mining pools become centralised and owned by pro ESG shareholders. that’s not a risk to drivechain specifically. That’s a concern for bitcoin in general.
(4) Rootstock is a merge mined federated sidechain and has been up and running for 5+ years now with no down time. ~$80 million of bitcoin in TVL currently with 60% of btc miners supporting the chain.