Major version number updates mandate real changes. This changelog reads like a bug fix release.
Speaking as a game developer, version numbers mandate diddly squat. There is no standard for versions, not even guidelines. Every single company treats version numbers different, and many, even big ones, change how they do their numbering at some point - for example, Mac OS climbed steadily to 9.2.2, then got stuck at 10.x.x for the next 16 years (so far). nVidia releases a new driver roughly every month, those drivers are mostly bug fixes and optimizations, their version number jumps up by 3 on average no matter whether its a small change or major features added.
So lets look at Nintendo. Version 2.0.0 on launch day, added features that Nintendo considered important enough to list. Versions 2.1, 2.2, 2.3, those were bugfix releases that did nothing of note (General system stability improvements to enhance the user's experience). Version 3.0 added a number of features that Nintendo considered important enough to list. So Nintendo advances the first number when they add features they consider worth listing. In this case, they enabled the USB ports, added a bunch of quality-of-life features, and fixed some of the largest issues that people complain about - for Switch, this *is* a major release.