It didn't literally fall into the ground, because it was still retained attached by a few electric cables, but yes all the mechanical parts to keep it attached were gone and the lid was kinda dangling.
The lid internally is surrounded by a light-metal (aluminum?) frame which runs around the screen edges and this is the only mechanical structure inside the lid. This frame then is fixed to the two hinges on the bottom, which are also metallic (strong, heavy-duty steel).
As I found out to be a common defect with all the Acers in the Extensa series, the light aluminum frame cracked, leaving the lid disjointed from the hinges and hence free to fall down. That is, the steel hinges are so heavy and friction-ful in these models that they crack the frame, especially after years of usage when their lubricant dries and they harden even more.
I gotta fix it.
New frame brackets on eBay and other bays where kinda expensive (€15 each, x2) for what they actually are (they are nothing.. just an aluminum plate cut in shape), so I fixed it in-house, in my computer hospital.
I found a spare tick steel plate around, fitted for the job. By this point the images will continue the narration.