The "era of ferment" is an interesting concept generally speaking, but hardware wallets are not required for sovereign ownership of Bitcoin. In fact, they are a weakness. In my opinion, we will move away from hardware wallets altogether and work exclusively with trusted battle-tested FOSS software wallets such as Electrum and Seedsigner. BIP39 seed phrases will be stamped on stainless steel washers or some other form of durable media and physically secured. I further predict that hardware wallets will get compromised with Gov't/corporate mandated back-doors further eroding trust in all of these devices.