There are lots of risks of hot wallets, Apple or Google committing seppuku by pushing an update that confiscates their users’ money (LOL) is probably the literal least likely way you can lose money from hot wallets.
Balaji is suggesting that hot wallets are necessary for a bitcoin economy and that’s why we need technological and political solutions. He’s right that hot wallets would indeed be a long term risk. iOS and Android could be a huge single point of failure in a political attack on bitcoin. But the answer is not developing ways to securely store keys on iOS and Android devices. The answer is never storing keys on iOS and Android devices.
You can already use iOS and Android to conveniently interact with bitcoin while never storing a private key on the device itself. See Ledger Nano X w/ Bluetooth and Block’s forthcoming BitKey.