I think you have a fundamental misunderstanding about what TXT and/or trusted computing are for. They are not technologies that prevent compromise. There main point of their existence is for you to be able to get a a verifiable list of software on your machine. Nothing more and nothing less. IOW the main point is so that you can reliably tell when you have been rooted not to prevent being rooted.
Now for specific examples. In a TXT enabled hypervisor the ethernet device is not part of the tree of trust. That is the point behind TXT. In classical Trusted Computing (TC) it would have been but TXT was created so that a hypervisor does not have to trust the: BIOS, system firmware, or OS that launched it.
Now for your wireless driver buffer overflow example. In a TXT style system there is going to be a hypervisor and it protects itself from all of the OS's that it is in control of via hardware protections (basically IOMMU with page protection lists). Some OS partition will be where that wireless driver exists. So when someone exploits that flaw and roots that OS partition then the hypervisor should be able to tell (new executable pages come in to existence or the contents of executable pages change). So it has done its job and let you know that said partition is rooted.
I will repeat this to make it crystal clear. TXT is not a mechanism to protect you from software faults. Its just the most basic mechanism to allow you to reliably know what software is running on your machine. You still have to build the rest of your security stack on top of that. Its just trying to lay a sound foundation on which to build better security, It in and of itself is not some silver bullet.