I don't see what it is you're trying to point out. It looks like functionally the same product to me. The only difference is that UpCart is collapsible - is that what you were getting at?

That difference will potentially get you a patent on the combination (not the wheels part). The YouTube clip and item referenced above is fixed (appears far more industrial as well), with no folding or contracting parts. One of the selling points of the Stair Climber supposedly is its ability to "fold completely flat for easy storage or transportation." It also appears a lot lighter, easier for someone to throw in the trunk and haul around. That's a big product difference in the market. One you sell for $300 for heavier industrial purposes (the YouTube cart looks like it could take a beating in a warehouse for a decade), the other you sell for $79.95 for household use or to small businesses with more modest needs.

Is it a radically new invention. No, it's an improvement or variation on an existing product.

We were using non-collapsible stair-climber shopping carts in Singapore since at least 2011. It was about 30 USD.

We know what he claimed to invent, but the point is that he didn't actually invent any of those mechanisms. They've been around for decades. At best this is incremental development on existing stairclimber trolleys. https://en.wikipedia.org/wiki/Stairclimber

Over a century in fact - https://patents.google.com/patent/US849270A/en