Nah, I mean having to mess with adapters. What I'm saying is, seeing as how the entire industry is moving toward USB-C form factor, having a TB interface also as you mentioned for power delivery in case you don't want to use the power brick, would be a pretty cool thing (most TB provides more than enough power delivery to something like a DAC or even interface).
I'm also saying I doubt people who are buying these devices are so price sensitive that something like USB 2 needs to be entertained. Then again, I have a problem with many DACs these days only offering the standard 3 input I/O. I really would like to see more inputs, like dual Optical, Dual USB (so you can have TB, and a standard old USB2 interface if you feel ruggedness is that much of a concern).
Finally, USB-C has no issues staying plugged in. Most of the USB-C devices you see, are just shit tolerances. If you have a chance to try a Macbook for instance (or it's USB-C power adapter) you'll see just how well USB-C clicks into place and stays there. If there is really some sort of compelling argument about ruggedness of USB2 connectors, it would have to be made for products that are transported a lot. Once I plug in my inputs, I generally don't wonder (oh man, my desk is like an earthqake, and my floor is riddled with connectors, I sure hope my USB-C cable doesn't get unplugged from my DAC/interface). I don't see that as a talking point that USB2 solves where USB-C fails. If such was the case, you would see laptop still sporting USB2 (since those actually do get plugged and unplugged many times.