A little knowledge is a dangerous thing. If you buy a regular treasury yielding 5 %, you are locked in. If inflation jumps to 5%, your real return on your original investment is zero. An efficient market will give you a higher yield on your next bond purchased. If you were correct in your logic there would be no market/demand for inflation adjusted bonds.
Quite true. Given two investments of different risk, the riskier will be priced to yield more. Nothing you say negates this very fundamental fact of investments.