Yeah exactly. Switch and Wii are very different beasts, and the markets they went after and the sales paths they have followed are very different from one another.

Wii had a big first holiday + first calendar year but was held back by shortages as word of mouth of motion controls swept the world. Years 2 and 3 were Wii's monster 24/22 million calendar years as the blue ocean buying frenzy hit its peak, and then things began to fade hard as blue ocean consumers lost interest. Year 4 it still sold very well but was in fast decline as interest in it was falling hard so that by year 5 it was all the way down to 10 million. Year 6 it was dead, selling current Xbox One levels.

Switch on the other hand, had a great first three-quarters calendar year but was also held back by shortages. Year 2 built momentum. Year 3 built more momentum. Year 4 (2020) sales finally exploded into top Wii-like numbers, and if Nintendo can make enough it will likely top Wii's best year. Rather than a first-half-of-the-life-cycle buying frenzy that the Wii had, followed by a sharp decline, the Switch has built momentum up through its first few years and doesn't look like its going to be slowing down any time soon.

That's because Wii's market selling craze audience was non-gamers, who buy a few games and then lose interest after a while, while Switch's market selling craze audience are gamers who want to play console games anywhere - this is why software sales are so much higher than the Wii despite similar hardware numbers so far. At this point in the Wii's life sales started to nosedive, though the next year was still very good sales since even a nose dive from its peak numbers is still a lot of sales, but within one year from now Wii was comparatively on life support. Nobody expects Switch sales to start a hard decline immediately and dry up in a year. In fact Switch's 5th calendar year (2021) is likely to be around double the sales of Wii's 5th calendar year (2011).

To summarize, the Switch is experiencing an insane sales craze right now in year 4, while the Wii had its similar sales craze in year 2, entirely different sales profiles.

Once it reaches the magical 110 mil. mark it really gets interesting how far those legs reach. For comparison, I think it's a fair bet that the PS4 will pass 130 mil. lifetime, probably will reach 138 mil. Once the Switch is at that 110 mil. mark and it is as healthy as the PS4 (or even a bit healthier) was at that mark, it looks promising to reach those 138 mil. as well.