Most of it isn't actually that expensive. The examples in the article are extremely rare or perfectly mint copies of very old games. A rare unopened copy of SMB sold for 1.5 million but that doesn't mean a loose Mario bros/duck hunt cartridge with scuffed label is worth more than $5. Same for some of the old computers i have in my attic, they are worth something but still sub $100, barely worth the effort of going through the trouble of listing and shipping them. Never mind storing them for decades.

This seems to be mostly over now. Prices on ebay have fallen considerably in the last 6 months in my experience.

An SNES with a couple games still sells for like $300

Nintendo is the exception. I think the rising prices of nintendo stuff temporarily inflated everything else but only nintendo has big enough demand