Hello Patrick. I cannot agree with your brief statement that the “eGPU box is already massively bottlenecking a GTX 1080”. On the pages I linked to above, and in particular the posts by “Enjoy”, there is some extensive testing and analysis of differing configurations. Bottlenecking is more accurately termed throttling, I suggest, and the estimates are that half of the throttling is due to limitations of the laptop CPUs and interfaces when compared with a desktop system. When using an external display the reduction in performance is typically 20% lower than a desktop system with the same type of GPU, but if then sending the video display data back tot he laptop’s internal display than that drop does increase to 30-40%. Note that these performance drops are lower when the game or benchmark test is biased towards being CPU-intensive (a minority of cases, it appears), and the key is that the playability remains very strong using any of the current mid- to high-end GPU cards. A different world from Intel or other integrated solutions!
Please note that there have been issues with some of the earlier TB3-equipped laptops/convertibles, and even with the HP x360 15 that has a discrete GPU, in which only half of the full 4 lanes have been connected so only providing 16Gbps of bandwidth rather than 32 and effectively performing as a TB2 interface. Most of the more recent TB3 interfaces do appear to have enabled the full 4 lanes.
Also note that Apple will apparently release their own eGPU box, which is why they are now directly offering their developer kit using the current Sonnet box bundled with a GPU. I think Eve is very well placed to introduce a more competitively priced eGPU device than any other vendor, and hence can maintain a competitive edge. eGPU enclosures are simply too expensive for what they are, right now, perhaps with some parties recouping early development costs which will now not apply to other Windows/Intel vendors as the firmware/driver development work for plug-and-play has already been done. Perhaps in three or four years from now there will be no need for eGPUs at home/desk, but the current hardware for truly portable mobile devices with good battery life is not available.