I certainly agree with your second statement; see my comments above.
For the first, I'm not sure requiring HW is a non-starter. It would have to be cheap---say $20 or less---to start with. Eventually, motherboard manufacturers would just start throwing it on the board, increasing the price of the board by $.50 given reduced costs and increased volume. We've seen that pattern over and over with dedicated hardware. Another possible path in this case is to make an append-only store controller part of the TPM spec (if it isn't already---I haven't looked).
There was a time (and I lived through it) where it was believed that memory protection hardware for microprocessors was a non-starter. Eventually people decided to pay: partly for security reasons. So there's some hope.