I believe the person who wrote the "3 different versions of Switch" message is missing the mark a bit. If Nintendo follows up their initial hardware with an update later, it really should incorporate the flexibility of the platform rather than just offer the single format a person is looking for (despite how convenient that sounds). I instead see Nintendo upgrading the existing system piece-by-piece.
If they need to update the Joycons, it's as easy as releasing the new version a couple years later. If they need to enhance the performance, the external processing patent may suggest a dock with that wireless capability down the line. Again, new Joycons could allow for this same feature on-the-go. They can even replace the main tablet portion when it's just not worth supporting anymore, which could be seen as "the new console launch." And the best part? Instead of making the consumers buy a whole new system repeatedly, they would only have to pay the $90 or so that the new part would cost. Meanwhile, all existing starter bundles would have all the latest components and still retail for the same price, as theoretically the earlier Switch would be lower in cost following the necessary amount of sales (which Wii U never achieved). It would be easy for both new and old customers to stay current. This pattern could go on until Nintendo needs a completely new structure.