"but", I hear you retort, "the roots just work out so perfectly! I can perfectly predict exactly what word a root will become in any of the daughter languages!"

No shit they work out perfectly, because they're all made up. Nobody actually said *dheh1. That was never a real word. That it lines up with a real word is because we made it to. We don't even have any way to prove these words were ever spoken in the way we think they were.

"but actually we found a language with one of the hypothetical laryngeal consonants 50 years after we made them up", no, you found a language with a letter for a sound you didn't know and you slotted into the system that you just made up which nobody 50 years earlier would have even thought to use, because it's all made up, and only one consonant even fit in the made up model anyway

P.S. Fuck you Simon Roper.