I was going to make a thread about this due to something that happened to me recently.
To answer your questions: Long story short......Heritage & other auction houses & grading services are gearing up to make sealed VHS tapes the next thing. They are working to get all the historical info they can via experts & ex-industry vets & buying up stock left & right.
I not one but two sealed copies of Alien. I thought one was the first print & the other was the third. I too thought the ending prices had to be fake or some shiz, but still I listed the two together with a sealed copy of alien trilogy for good measure. I started the BIN at market ($1,900) & the lot sold in less then 10 minutes.
It ended up being someone tied to the auction industry. Nice enough guy. He will buy desirable titles for market to speculate with so you can't go wrong there. Plus he helped me with identifying some original anime cells & sketches that I found years back when thrifting.