Pokemon keycaps, high end devices like the Analog Pocket get sold out, there's a new gaming console every second...all of this makes one wonder...why is retro gaming so popular? The answer is pretty simple actually!
The valley of Obsolescence
Products, like the Gameboy, Ipod & the like follow a well-defined lifecycle. At first, they are new and amazing, then some new "thing" replaces them (like the iPhone to the iPod) and the old gets thrown out and forgotten.
When smartphones became a thing, all PDAs, iPods and the like were all thrown out in the bargain bin because once these devices became obsolete nobody cared about them. Replace smartphone with GBA or DS. Once these consoles came around the old was discarded.
The Nostalgia factor
But then, invariably, something predictable happens. The people who dismissed these items MISS them and seek them out again. I had a Nintendo DS and I never thought I would miss my Gameboy but here we are.
Same thing for the iPod users, these are still selling strong in second-hand markets to this day. Of course the iPods and game consoles have some modern conveniences like SSD and upgraded LCDs backed in, but it's all about trying to preserve a piece of our past.
We ain't kids no more
The reason why retro gaming is so popular is exactly for the reason above: All of the kids who had the Gameboys and the DSes are now all grown up and want a piece of their past back.
That is the biggest reason why Retro gaming is so popular. Here's something else: It's also predictable. If your child's first console was the Nintendo Switch, in 10-15 years this will be a retro console.
The previous generation like the Gameboy will fade out in the same way that many do NOT have any nostalgia for pre-NES consoles (like the Atari) and something else will replace it.
Video games being a relatively recent invention, it's the first time in history that the kids that had it have all grown up and got their own money to spend. But the cat is out of the bag, as more and more consoles get released, more and more people will be exposed to them and get nostalgic about them in a decade or so.
But here's an important caveat: The current popularity of video games is relative to the popularity of said video game in the past. Many will be nostalgic about the GB, GBC, GBA and more but probably not the Virtual Boy as it never really was popular.
This is also dependent on the country. The West might not have a "thing" for the PC98 but the Japanese absolutely do!
So if you are wondering why retro gaming is SO popular, it's simply because the kids who had them as the latest and greatest are now all grown up and want to relive a part of their childhood.