The TCPA does not address this scenario at all

While the TPCA doesn't give away its storage encryption key easily, you still need to have the
unwrapped (aka unprotected) session key for your encrypted disk somewhere in main memory to
work with it.

The complete fix for this problem really goes through extra hardware.  Designing
extra-volatile memory is easy, but you need to get that memory inside a more protected
location (like inside the MCH, CPU, or data storage unit itself).  And an attacker with enough
resources would still be able to get to it.

What we can do easily, is to reduce the windows of opportunity where the keys are available
unprotected in RAM, which is good enough for a lot of scenarios.

Frankly, if it can be made safe enough that regular laptop and data thieves can't get to the
data, I would be personally happy enough.