I think that with normal watering practices (vs S/H method) the dead roots would not be a huge problem. I think this because the hydrotron or prime agra type media allows so much air to the roots. They will eventually break down while providing slow release nutrients to the plant. Watering would rinse out excess toxins.
Do I know this for a fact? No, but I have no reason not to either.
At some point the plant will NEED to be required. I don't know of many people that can keep an infinitely large plant. Root maintenance could be done at that time.