It’s entirely possible, just like perpetual motion and faster than light drives. Just because people say it can’t be done now, doesn’t mean it won’t be done 100 or 1000 years into the future.
There’s an objective difference between “can’t be done” vs. “it’s really hard”. Perpetual motion & faster than light transport are “can’t be done”; no amount of time will make it possible (interesting alternatives, maybe). Large-qbit-count quantum computers are “really hard”; given enough time we’ll figure it out and we’re well on our way now.
Refresher on the Laws of Thermodynamics:
1. You can’t win
2. You can’t break even
3. You can’t get out of the game.
Hence no perpetual motion machines.
Energy required for acceleration has asymptotic increase as you approach the speed of light. You can’t get, or pass, that speed without expending a literally infinite amount of energy.
Quantum computing, however, has already been achieved. As time passes the number of bits in the computers are increasing exponentially.