There's something that intrigues me, assuming a March 2025 launch for the successor. What happened for Nintendo to need more than eight (08) years to release their Next Gen Hardware?
They didn't
need 8 years, they just decided to take 8 years. In an ideal world, no new hardware is
ever required. The insanity of a world where some television and movies were exclusive to some brands of television, and periodic upgrades were required to play the latest shows.
Nintendo obviously could have released new hardware years ago, if they wanted. Not as powerful and/or cheap as the hardware we're going to get, but they still could have done it. They also could have skipped new hardware entirely for a few more years. There is no technological reason to keep next Mario for the new hardware, or Mario Kart 10, or Luigi's Mansion 4, or 3D Kirby 2, or Donkey Kong Country 6...
Nintendo could continue to sell hardware mostly as replacements and upgrades, lowering the price to increase volume, and churning out their incredible first party games for another 5 or 6 years, and still be tapping their main franchises less than their competitors. The problem isn't internal, it's external. 3rd party games would dry up as Switch got left behind technically, first party games would stagnate visually even if gameplay-wise they remained innovative, and Microsoft and Sony would smell blood in the water and make a play to claim the handheld market that was financially ready to buy new hardware that Nintendo simply wasn't selling them.
Nintendo would probably also run into talent retention problems if they didn't let their most talented developers and designers pursue new challenges outside the limitations of the existing hardware. They'd have gamer retention problems as folks ready to buy a new console were only presented with competitors as options, potentially leaving the Nintendo ecosystem, and not coming back.
These are the reasons that Nintendo are going to eventually make a next generation device. But their device is so popular, and their game development has been so rock solid, they could afford to wait. And I think we're likely getting a much more powerful device because of that wait. Nintendo knows the next generation will also probably be long, so they need hardware that will age well, and they designed the system with cutting edge technology, knowing that an extra year of waiting won't significantly age the hardware, but will significantly drive down costs.