Typical Snowman...
Canadian Tire's Baja ATVs are rebadged Yamaha machines. As such, any decent motor sport store will have access to replacement parts. You just have to give them the Yamaha part number. In fact, since a fair number of the components are universal, suitable replacements can be found (with a little more digging) at many motor sport stores.
Not sure about Walmart's offerings: they're big enough to have someone manufacture stuff specifically for them, so...
Canadian Tire's Baja ATV’s are great if you going to let your kid run on the back lawn. There is a reason they are only $1200. One trip on a “real” trail with uneven ground or water and you will find out why. The tires are way to small, the battery is too weak, cheap drive chain, loose bolts, poor carburetor needing constant adjustment, and good luck if you have a problem and go to Crappy Tire for warranty work or service.
I did not realize you were so knowledgeable about ATV’s X, do you own one and ride them?
Wow. Completely forget about this thread.
But to answer your question of, oh, two years ago...

I'll agree that they're no good for
real off road riding. But I would think and hope anyone who does any real riding would know that. They're great just to have some fun on around the house or on some kept trails. Certainly not something I would take on a real expedition, though.
We did have the Baja 90 for a bit, sold that one because it lacked power and a reverse gear. Now have the Baja 250 4x2, and it's been a good machine for casual play. Not suited to the sort of riding you do, Snowy, but good enough for our needs. The nice thing is they are Yamaha designs, so if you're willing to do a little digging you can find parts for them from anyone that carries Yamaha stuff.
One day I'll buy a proper ATV. In Mexico a couple years ago we went on an ATV trip, down through the forest and the beach... what a blast!