I believe we will have shortages of Ring Fit during holidays. It's a surprise hit for Nintendo after the average sales of the other motion controlled games like 1-2 Switch, ARMS and Labo. Even some of my online friends play Ring Fit although they didn't touch the other mentioned motion control games.

Ring Fit > VR
This is the future of RPGS!!!!

Persona 5R took a big hit, while Luigi 3 is going strong still. Basically P5R was there to keep Luigi from ever getting the top spot even though Luigi 3 will outsell it in the long run. Then there is Ring Fit Adventure. Game is actually up 2% since last week. Hard to get a much stronger hold that that week-over-week. It's going to have incredible legs.

Disregarding the fact that each game sold over two million copies which I'd not call average, that you've included Arms which does not have mandatory motion controls, and that you've disregarded other games with either mandatory (Super Mario Party) or optional (Mario Kart 8), motion controls, I'm sure Nintendo was smart enough not to base their expectations on the sales of three other games that have almost nothing in common with Ring Fit.  

The OG model managed to do by itself a bit better than last year.

P5R DEFINETLY felling the loss of the PS3 as a platform compared to p5 and compared to persona 4 Golden's status as a handheld title.

Probably positive word of mouth.  Most people have played the game, so far as I've seen, have been pleasantly surprised.

Switch sales are at the same level as week 50 last year... damn. I know 4 million for the year is almost certain, but can it hit 4.5 million? That would be pretty damn good... 5 million would be better, but that may be a bit too much to ask for.

How did wii fit compare, week to week?

It was sort of similar, but not quite the same.  Wii Fit started much higher, and after launch the numbers swung around pretty widely for a few weeks, hovering around 150k.  The numbers would go up or down from week to week by about 50k or so, which seems to imply shortages, I think possibly moreso of the Wii itself than the game.