Very true, let take some trip down memory lane, did drone kill the camera man using an helicopter to broadcast news event happening? No. Did Uber kill the local taxi driver driving everyday in the street to get his daily bread? No. Did email kill, sending and recieving of letter through the post office? No. Sure this new innovations did reduce the rate at which people use the formal but they're still operating fine. That's what will happen with bitcoin and banks. Non is replacing the other instead both with operate just fine and it's left for you to decide on which to give the upper hand.
This is correct. There will always be demand for private-key custodial institutions.
Most people would be better off keeping their coins on Gemini or Coinbase rather than stored locally. This is due to the technical incompetence of the vast majority.